94 Questions

Sample Final Exam

Questions and Answers

- 1.
- A.
Likely to be biased because students are less likely to be enrolled during the Summer term.

- B.
Unreliable because surveys are never as good as experiments.

- C.
Unreliable because the sample size should be at least 500

- D.
Unbiased because SRS was used to get the addresses.

- 2.The following histrogram is a distribution of Religiosity of 226 people. What percent of these people had Religiosity in the 56-60 Religiosity range?
- A.
31%

- B.
41%

- C.
51%

- D.
61%

- 3.Appropriate graphical summary of the distribution of a categorical variable
- A.
Bar graph

- B.
Box plot

- C.
Stemplot

- D.
Residual plot

- E.
Scatter plot

- 4.A researcher wants to know the average dating expenses for BYU single students. The researcher obtained a list of single students from the Records Office who live in the BYU dorms. From this list , 50 students are randomly selected. The 50 students are contacted by phone and the amount they spent on dates are recorded. The average dating expense of the 50 students is $35 with a standard deviation of $8. What is the population of interest?
- A.
Average dating expenses of students

- B.
All BYU Single students

- C.
The 50 students selected

- D.
All BYU students

- E.
The number of single students who spends between $20 to $50 on date

- 5.What does probability sampling allows us to do
- A.
Make inferences about population parameters

- B.
Removes sampling variability

- C.
Assess cause and effect relationship

- D.
Exactly represents the population

- 6.Following is a five-number summary of the number of dates, before getting married, of 100 BYU students. Min Q1 Median Q3 Max 10 40 80 100 500 about 25% of the students participated in more than ______________________ dates before getting married.
- A.
10

- B.
40

- C.
80

- D.
100

- E.
500

- 7.Which research method can show a cause and effect relationship between the explanatory and response variables?
- A.
A sample survey based on a simple random sample of single students.

- B.
An observational study based on a carefully selected large SRS of single students.

- C.
A comparative experiment where each single student is randomly assigned to one of two treatments

- D.
A study using single students where the males are given the treatment and the females were given the placebo.

- 8.Given the figure below: If basketballs X, Y, and Z are added to the group of five balls at the left, how will the standard deviation of the volume of the new 8 balls compare with the standard deviation of the volume of the original set of 5? The standard deviation of the volume of the new set of 8 balls will be _________ the standard deviation of the volume of the original 5 balls. Fill in the blank.
- A.
Will be about the same

- B.
Will be greater than

- C.
Will be less than

- D.
Cannot be compared to

- E.
Cannot be computed since the balls are such different sizes

- 9.The standard deviation of Stats221 Final scores for a sample of 200 students was 10 points. An interpretation of this standard deviation is that the
- A.
Typical distance of the Final scores from their mean was about 10 points

- B.
The Finals scores tended to center at 10 points

- C.
The range of Final scores is 10

- D.
The lowest score is 10

- 10.After a Church game, Jeremiah scored 40 points. His coach, who is a Statistics teacher, told him that the standardized score (z-score) for his points on the game, is 2.5. What is the best interpretation of this standardized score?
- A.
Jeremiah’s score is only 2.5

- B.
Only 2.5% of the players scored higher than Jeremiah

- C.
Jeremiah’s scoring is 2.5 times the average scoring in the league

- D.
Jeremiah’s scoring is 2.5 standard deviations above the average scoring in the league.

- E.
Jeremiah’s scoring is 2.5 points above the average scoring in the league

- 11.For a particular set of data, the mean is less than the median. Which of the following statements is most consistent with this information?
- A.
The distribution of the data is skewed to the right

- B.
The distribution of the data is skewed to the left

- C.
The distribution of the data is symmetric

- D.
"mean is less than the median" does not give any information about the shape of the distribution.

- 12.Which of the following data sets has the largest standard deviation?
- A.
2, 3, 4, 5, 6,

- B.
301, 304, 306, 308, 311

- C.
350, 350, 350, 350, 350

- D.
888.5, 888.6, 888.7, 888.9

- 13.
- A.
Changing the unit of measure for x changes the value of r.

- B.
The unit measure on r is the same as the unit of measure on y.

- C.
R is a useful measure of strength for any relationship between x and y.

- D.
Interchanging x and y in the formula leaves the sign the same but changes the value of r.

- E.
Where r is close to 1, there is a good evidence that x and y have strong positive linear relationship.

- 14.
- A.
Is important enough that most people would belive it.

- B.
Has a large probability (P-value > alpha) of occurring by chance.

- C.
Has a small probability (P-value < alpha) of occurring by chance.

- D.
Is important enough to make a meaningful contribution to the relevant subject area.

- 15.The following bivariate data was collected.
Advertizing 80 95 100 110 130 155 170 Sales 40 55 75 90 220 290 760 - A.
Every observation is an outlier

- B.
There is no association between x and y

- C.
There is a curved association between x and y

- D.
There is a strong positive linear association between x and y

- E.
There is a strong negative linear association between x and y

- 16.
- A.
Figure A

- B.
Figure B

- C.
Figure C

- D.
Figure D

- E.
None of the above.

- 17.The following data are from a study of the relationship between Stats221 Test3 scores and the Final scores. The response variable is Final scores (FS) and the explanatory variable is Test3 scores (TS).
TS 90 81 75 94 65 FS 88 84 78 93 60 - A.
On the average, FS increases by about 1.4 units when the Test3 score increases by 1 unit

- B.
On the average, TS increases by about 1.4 units when the Final score increases by 1 unit

- C.
The correlation between FS and TS is 1.4

- D.
The proportion of variation in FS that is explained by the regression model is 1.4

- 18.An SRS of households shows a high positive correlation between the number of televisions in the household and the average IQ score of the people in the household. What is the most reasonable explanation for this observed correlation?
- A.
A Type I error has occurred.

- B.
Large households attract intelligent people.

- C.
A mistake was made, since correlation should be negative.

- D.
A lurking variable, such as higher socioeconomic condition, affects the association.

- 19.Which of the following is the conditional distribution for college Majors for students whose last Math class taken was College Algebra?
- A.
A

- B.
B

- C.
C

- D.
D

- 20.The BYU records office found that 80% of all students who took Stats221 at the BYU Salt Lake Center worked full-time. The value 80% is a
- A.
Mean

- B.
Statistic

- C.
Parameter

- D.
Margin of error

- 21.The Central limit theorem allows us
- A.
Know exactly what the value of the sample mean will be.

- B.
Specify the probability of obtaining each possible random sample of size n.

- C.
Use the standard normal table to compute probabilities about sample means and sample proportions from a large random samples without knowing the distribution of the population.

- D.
Determine whether the data are sampled from a population which is normally distributed.

- 22.In a large population of basketball players whose scores are left skewed, the mean score is 16 with a standard deviation of 5. 100 members of the population are randomly chosen for a research study. The sampling distribution of x-bar , the average score for samples of this size is
- A.
Approximately normal with mean=16 and a standard deviation of 0.5

- B.
Approximately normal with mean=16 and a standard deviation of 5

- C.
Approximately normal with mean=sample mean and a standard deviation of 0.5

- D.
Approximately left skewed with mean=16 and a standard deviation of 5

- 23.The sampling distribution of a statistic tells us
- A.
The standard deviation of the population parameter.

- B.
How the population parameter varies with repeated smples.

- C.
Whether the sample is from a normal population provided the sample is SRS

- D.
The possible values of the statistic and their frequencies from all possible samples.

- 24.The speed at which cars travel on I-15 has a normal distribution with a mean of 60 miles per hour and a standard deviation of 5 miles per hour. What is the probability that a randomly chosen car traveling on this highway has a speed between 75 and 63 mph?
- A.
.2729

- B.
.9918

- C.
.50

- D.
None of the above.

- 25.What is the primary purpose of a confidence interval for a population mean?
- A.
To estimate the level of confidence.

- B.
To specify a range for the measurements.

- C.
To give a range of plausible values for the population mean.

- D.
To determine if the population mean takes on a hypothesized value.

- E.
To determine the difference between the sample mean and population mean.

- 26.Explain the meaning of “95% confidence interval “.
- A.
There is a 95% probability that the interval contains x-bar.

- B.
The interval contains the value of x-bar with 95% confidence.

- C.
95% of the data is contained in the interval.

- D.
For 95% of all possible samples, the procedure used to obtain the confidence interval provides an interval containing the population mean

- 27.In hypothesis testing, what does the symbol αdenote?
- A.
The power of the test.

- B.
The probability that Ho is true.

- C.
The probability of Type II error.

- D.
The probability of Type I error.

- E.
The probability of rejecting a false null hypothesis.

- 28.
- A.
0.0082

- B.
0.9918

- C.
0.5

- D.
None of the above.

- 29.A simple random sample of full-time workers in the U.S. involved 817 full-time employees aged 40-50. They were asked to give their educational level (no high school, high school, some college, bachelor degree, some graduate education) and their level of financial satisfaction with their job (well satisfied, somewhat satisfied, not satisfied). The following MINITAB output is from the chi-square program. Rows are educational levels and columns are satisfaction levels:Ho: The proportions of people who are well satisfied financially are the same for all educational levels.Assuming Ho is true, what is the expected count for people who completed high school and not financially satisfied.
- A.
85.4

- B.
95.6

- C.
100.5

- D.
104.6

- 30.A simple random sample of full-time workers in the U.S. involved 817 full-time employees aged 40-50. They were asked to give their educational level (no high school, high school, some college, bachelor degree, some graduate education) and their level of financial satisfaction with their job (well satisfied, somewhat satisfied, not satisfied). The following MINITAB output is from the chi-square program. Rows are educational levels and columns are satisfaction levels: Ho: The proportions of people who are well satisfied financially are the same for all educational levels. Referring to question above, what are the degrees of freedom for the chi-square statistic?
- A.
2

- B.
4

- C.
6

- D.
8

- 31.
- A.
No, because more than 20% of the components of the chi-square statistic are less than 5.

- B.
No, because all expected counts are not whole numbers

- C.
Yes, because all expected count are greater than 5

- D.
Yes, because n is greater than 30

- 32.A simple random sample of full-time workers in the U.S. involved 817 full-time employees aged 40-50. They were asked to give their educational level (no high school, high school, some college, bachelor degree, some graduate education) and their level of financial satisfaction with their job (well satisfied, somewhat satisfied, not satisfied). The following MINITAB output is from the chi-square program. Rows are educational levels and columns are satisfaction levels: Ho: The proportions of people who are well satisfied financially are the same for all educational levels. Based on the analysis in question 1, we conclude at alpha=0.05 that
- A.
The proportions of people who are well satisfied financially are not all equal for all educational levels

- B.
The proportions of people who are well satisfied financially are the same for all educational levels

- C.
There is no evidence of an association between educational level and financial satisfaction

- D.
Cannot be determined

- 33.An experiment is performed to examine the effect of three different dating activities on the rate of marriage of BYU single students. Twenty one subjects are randomly assigned to one of the three dating habits. What are the appropriate null and alternative hypotheses. a. Ho: µ
_{1 = }µ_{2 = }µ_{3 }versus Ha: µ_{1 }NE_{ }µ_{2 }NE_{ }µ_{3}b. Ho: µ_{1 = }µ_{2 = }µ_{3 }versus Ha: At least one of the means is different from the others.c. Ho: p_{1 = }p_{2 = }p_{3 }versus Ha: Not all the proportions are equal.d. None of the above.- A.
A

- B.
B

- C.
C

- D.
D

- 34.Experiments was conducted on how long in months it takes dating single students get married.For one particular Ward, the mean time is 12 months. Drew thinks that getting a 2% extra credits in Stats class for dating cause these students to marry faster. He plans to measure how long it takes for 20 dating students to get married with the extra credits as a stimulus. What are the appropriate Ho and Ha?a. Ho: µ = 20 versus Ha: µ < 20b. Ho: µ = 12 versus Ha: µ < 12c. Ho: µ = 12 versus Ha: µ > 12 d. Ho: µ = 12 versus Ha: µ NE 12e. None of the above.
- A.
A

- B.
B

- C.
C

- D.
D

- E.
E

- 35.Consider the following hypothesis:Ho: the incentive of 2% extra credits does not speed up marriage.Ha: the incentive of 2% extra credits does speed up marriage. Which of the following describes a Type I error?
- A.
Deciding that the incentive does not speed up marriage when the incentive does not actually speed up marriage.

- B.
Deciding that the incentive does not speed up marriage when the incentive actually speed up marriage.

- C.
Deciding that the incentive does speed up marriage when the incentive does not speed up marriage.

- D.
Deciding that the incentive does speed up marriage when the incentive actually speed up marriage.

- 36.
- A.
3.47 to 3.75

- B.
2.9 to 4.1

- C.
3.34 to 3.73

- D.
3.43 to 3.75

- 37.Which of the following is an appropriate graphical summary for displaying the relationship between bivariate quantitative variables?
- A.
Boxplot

- B.
Histogram

- C.
Stemplot

- D.
Bar chart

- E.
Scatter plot

- 38.
- A.
Using a confidence level of 90%.

- B.
Using a confidence level of 99%.

- C.
Using a sample of 100.

- D.
Using a different sample of 64.

- 39.Suppose that you were told that the statistical power of a test is 0.95. What does this mean?
- A.
The probability of failing to reject a true null hypothesis is 0.95.

- B.
The probability of rejecting a true null hypothesis is 0.95.

- C.
The probability of rejecting a false null hypothesis is 0.95.

- D.
The probability of Type I error.

- 40.A researcher wants to determine whether the time spent practicing free-throws after practice sessions can be used to predict the percentage free-throws in a game. What is the explanatory variable?
- A.
Time spent practicing free-throws

- B.
Number of practice sessions

- C.
Percentage of free-throws in a game.

- D.
Which method of shooting is used.

- 41.The following histrogram is a distribution of Religiosity of 226 people. How many of these people had Religiosity less than 34 Religiosity range?
- A.
6

- B.
8

- C.
12

- D.
20

- 42.
- A.
1.92

- B.
9.63

- C.
24.66

- D.
22.8

- 43.
- A.
0.0054

- B.
0.9946

- C.
0.2623

- D.
.0540

- 44.BYU Creamery sells 16-ounce box of ice cream. The weight of the contents of a box of ice cream has a Normal distribution with mean=16 and a standard deviation of 1.1 ounces. AN SRS of 16 boxes of ice cream is to be selected and weighed and the average weight of the 16 boxes computed.If we did not know that weight of boxes of ice cream is Normally distributed, would it be appropriate to compute the approximate probability that x-bar is less than 15.3 ounces using the standard Normal distribution?
- A.
NO, the sample size is too small to apply the Central Limit theorem.

- B.
NO, the mean of the sampling distribution of x-bar is not equal to the population mean.

- C.
YES, the sampling distribution of x-bar is approximately Normal.

- D.
YES, the conditions are met to apply the Central Limit Theorem.

- 45.An An NBA researcher believes that less than less than 60% of the professional players complete college education. A random sample of 100 players yields 58 who did not complete college education. The test statistic for testing Ho: p = 0.60 versus Ha: p < 0.60 is z= -1.94. What is the correct conclusion at the 0.01 significance level?
- A.
Fail to reject Ho: there is not sufficient evidence to conclude that the proportion of NBA players who complete college education is less than 0.60.

- B.
Fail to reject Ho: there is sufficient evidence to conclude that the proportion of NBA players who complete college education is less than 0.60.

- C.
Reject Ho: there is not sufficient evidence to conclude that the proportion of NBA players who complete college education is less than 0.60.

- D.
Reject Ho: there is sufficient evidence to conclude that the proportion of NBA players who complete college education is less than 0.60.

- E.
These players have a lot of money so they do need a college education.

- 46.Certain assumptions should be satisfied and checked with residual plots in order to make valid inferences in regression analysis. Which one of the residual plots below indicates that the condition of equal variances in NOT met?
- A.
A

- B.
B

- C.
C

- D.
D

- 47.
- A.
The New method has a significantly higher mean game scores than the traditional method.

- B.
There is insufficient evidence to conclude that the New method has a significantly higher mean free-throw shooting percentage than the traditional method.

- C.
The Traditional method has a significantly higher mean free-throw shooting percentage than the New method.

- D.
The New method has a significantly higher mean free-throw shooting percentage than the Traditional method.

- 48.The BYU Admisnistration is planning a student opinion poll.. Initially they suggest s ample size of 500. But upon investigation it is discovered that this will give rise to a margin of error that is too large. What should the administration do to correct this?
- A.
Decrease the sample size.

- B.
Decrease the population standard deviation.

- C.
Increase the sample size.

- D.
Increase the confidence level.

- 49.The BYU Admisnistration is planning a student opinion poll.. Initially they suggest s ample size of 500. But upon investigation it is discovered that this will give rise to a margin of error that is too small. What should the administration do to correct this?
- A.
Decrease the sample size.

- B.
Increase the sample size.

- C.
Decrease the confidence level.

- D.
Decrease the standard deviation.

- 50.
- A.
It is the probability of obtaining a test statistic that has a value at least as extreme as that actually observed, assuming the null hypothesis is true.

- B.
It is the probability of obtaining a test statistic that has a value at least as extreme as that actually observed, assuming the null hypothesis is false.

- C.
It is the probability of obtaining a test statistic that has a value at least as extreme as that actually observed, assuming the alternative hypothesis is true.

- D.
It is the probability of obtaining a parameter that has a value at least as extreme as that actually observed, assuming the null hypothesis is true.

- 51.A FOX News report claims a margin of error 4% with 95% confidence when reporting the proportion of people who oppose the gay marriage initiative. Which of the following is the best interpretation of this margin of error?
- A.
If the survey was conducted over and over again, 95% of the sample proportions will differ from the true proportion by no more than 4%.

- B.
If the survey was conducted over and over again, 4% of the sample proportions will differ from the true proportion by no more than 95%.

- C.
If the survey was conducted over and over again, 95% of the sample proportions will greater than the true proportion by more than 4%.

- D.
FOX News is not Fair and Balance according to ABC News.

- 52.
- A.
ANOVA

- B.
A two sample test of proportions.

- C.
A two sample test of means.

- D.
A matched pairs test

- 53.Coach Sloan claims that by using his method of shooting, basketball players can increase their scores by an average of 15 points. Wesley, a former basketball player is skeptical of this claim and wants to test the hypotheses: Ho: =15 versus Ha: <15 where represents the mean increase in scores of the population of all basketball players who have used the Sloan method. Wesley collects data from an SRS of 25 players who use the Sloan method. He finds that the sample mean increase in scores of these 25 players is 13 points with s=7. Assuming that the distribution of their scores is approximately normal, what is the p-value for this test?
- A.
0.0830

- B.
0.0228

- C.
.10>p-value>.05

- D.
.15>p-value>.10

- 54.Coach Sloan claims that by using his method of shooting, basketball players can increase their scores by an average of 15 points. Wesley, a former basketball player is skeptical of this claim and wants to test the hypotheses: Ho: =15 versus Ha: <15 where represents the mean increase in scores of the population of all basketball players who have used the Sloan method. Wesley collects data from an SRS of 25 players who use the Sloan method. He finds that the sample mean increase in scores of these 25 players is 13 points with s=7. What is the 95% confidence interval for the population mean?
- A.
13+-2.064

- B.
13+-2.89

- C.
13+-2.40

- D.
13+-5.37

- 55.The BYU Student Services conducted a student preference survey by taking a random sample from BYU-Provo, BYU-Idaho and BYU-Hawaii. The respondents were asked,"Do you prefer RMs or non-RMs or Non-LDS to date?" The percentages of respondents who preferred RMs in each of the three campuses were compared. What was the correct null hypothesis for this study?
- A.
A

- B.
B

- C.
C

- D.
D

- E.
E

- 56.There are 3 main campuses fro BYU: Provo, Idaho, and Hawaii. The BYU Student Services conducted a student preference survey by taking a random sample from BYU-Provo, BYU-Idaho and BYU-Hawaii. The respondents were asked,"Do you prefer RMs or non-RMs or Non-LDS to date?" The percentages of respondents who preferred RMs in each of the three campuses were compared. What is the sampling design used in this study?
- A.
A completely randomized block experiment.

- B.
An SRS.

- C.
A convenience sample.

- D.
A stratified sample.

- E.
A multistage sample.

- 57.A researcher for Presidential approval rating periodically conducts polls to estimate the proportion of people who agree that Pres. Obama is going a good job on the economy. The . researcher plans to triple the sample size in the polls. Why does the researcher plan to triple the sample size?
- A.
To decrease the standard deviation of the sampling distribution of the sample proportion.

- B.
To decrease the variation in the population.

- C.
To reduce the interviewer effect.

- D.
To reduce non-response bias.

- E.
To reduce confounding effects.

- 58.Coach Sloan is testing a new method of shooting free-throw and plans to randomly assign 20 players to the new method and 24 players to the current method. The mean percentage free-throw will then be compared between these two groups. What type of study is this?
- A.
A completely randomized experiment.

- B.
A randomized block experiment.

- C.
A matched pairs experiment.

- D.
An observational study.

- E.
A stratified sample.

- 59.Why do we do randomization in an experiment?
- A.
To do double blind experimetn.

- B.
To increase accuracy of the results.

- C.
To make the experiment realistic.

- D.
To help avoid selection bias.

- 60.What is the definition of the least squares regression line?
- A.
The sum of the residuals is minimized.

- B.
The sum of the residuals is optimized.

- C.
The sum of the squared residuals is minimized.

- D.
The sum of the deviations is small as possible.

- E.
The sum of the residuals equals to zero.

- 61.What is the advantage of randomized block design over a completely randomized design?
- A.
Variation associated with the blocking variable is removed.

- B.
Blocking is more accurate than the completely randomized design.

- C.
Blocking increases the precision of the experiment.

- D.
Blocking removes selection bias.

- E.
Blocking is illegal in basketball but not in football.

- 62.The table below gives the highest points scored by a player in a given year in the NBA from 2000 to 2009. What is the median number of points for these data?
2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 49 55 51 45 69 62 47 57 64 65 - A.
55

- B.
56

- C.
57

- D.
58

- E.
59

- 63.The level of good cholesterol in blood samples of 40 randomly selected middle-aged men is measured at the start of a two-month study. The men participated in the same exercise routine for the two-month period and then the level of good cholesterol is measured again. Researchers want to compare the mean levels of the good cholesterol and in order to do this, they should perform
- A.
A one sample z-test for mean

- B.
A one sample t-test for mean

- C.
A two sample z-test for means

- D.
A two sample t-test for means

- E.
A matched pairs t-test for means

- 64.After a statistical investigation, a researcher reports that “ in our sample, average expenses for a date was significantly higher (P-value=0.02) for married BYU students than for single BYU students.” What does the p-value in this statement tell us?
- A.
Only 2% of the BYU married students spend more on a date than the BYU single students.

- B.
The probability that the average expenses for a date for married BYU students is lower than those of the BYU single students is only 0.02.

- C.
The probability that the average expenses for a date for married BYU students is higher than those of the BYU single students is only 0.98.

- D.
If there were no difference in average expenses for a date between married and single students, the probability of observing a sample difference in average expenses for a date between the two groups is at least as large as that which was actually obtained, is only 0.02.

- E.
The probability that Ho is true is 0.02.

- 65.Consider the following regression output on the relationship between jaw width(in inches) of a shark (response variable) and length (in feet) of the shark (explanatory variable) for a random sample of 24 sharks. Scientists are interested in predicting a shark's jaw width from its length. Correlation coefficient: 0.8749 Estimate of sigma: 1.3757417
Parameter Estimate Std. Err. DF T-stat P-value Intercept 0.687864 1.299051 22 0.529513 0.5992 length 0.96345 0.082276 22 11.70994 <.0001 - A.
8.2%

- B.
59.9%

- C.
76.5%

- D.
87.5%

- E.
96.3%

- 66.Consider the following regression output on the relationship between jaw width(in inches) of a shark (response variable) and length (in feet) of the shark (explanatory variable) for a random sample of 24 sharks. Scientists are interested in predicting a shark's jaw width from its length. Correlation coefficient: 0.8749 Estimate of sigma: 1.3757417
Parameter Estimate Std. Err. DF T-stat P-value Intercept 0.687864 1.299051 22 0.529513 0.5992 length 0.96345 0.082276 22 11.70994 <.0001 - A.
<0.0001

- B.
0.0823

- C.
0.5992

- D.
0.8749

- E.
0.9634

- 67.Consider the following regression output on the relationship between jaw width(in inches) of a shark (response variable) and length (in feet) of the shark (explanatory variable) for a random sample of 24 sharks. Scientists are interested in predicting a shark's jaw width from its length. Correlation coefficient: 0.8749 Estimate of sigma: 1.3757417
Parameter Estimate Std. Err. DF T-stat P-value Intercept 0.687864 1.299051 22 0.529513 0.5992 length 0.96345 0.082276 22 11.70994 <.0001 - A.
A

- B.
B

- C.
C

- D.
D

- E.
E

- 68.Consider the following regression output on the relationship between jaw width(in inches) of a shark (response variable) and length (in feet) of the shark (explanatory variable) for a random sample of 24 sharks. Scientists are interested in predicting a shark's jaw width from its length.Correlation coefficient: 0.8749Estimate of sigma: 1.3757417
Parameter Estimate Std. Err. DF T-stat P-value Intercept 0.687864 1.299051 22 0.529513 0.5992 length 0.96345 0.082276 22 11.70994 <.0001 - A.
0.96+-0.171

- B.
0.96+-0.271

- C.
0.69+-0.171

- D.
0.69+-0.271

- E.
0.69+-0.371

- 69.Consider the following regression output on the relationship between jaw width(in inches) of a shark (response variable) and length (in feet) of the shark (explanatory variable) for a random sample of 24 sharks. Scientists are interested in predicting a shark's jaw width from its length. Correlation coefficient: 0.8749 Estimate of sigma: 1.3757417
Parameter Estimate Std. Err. DF T-stat P-value Intercept 0.687864 1.299051 22 0.529513 0.5992 length 0.96345 0.082276 22 11.70994 <.0001 - A.
The 95% prediction interval is not comparable to the 95% confidence interval.

- B.
The 95% prediction interval is the same as the 95% confidence interval.

- C.
The 95% prediction interval is wider than the 95% confidence interval.

- D.
The 95% prediction interval is narrower than the 95% confidence interval.

- 70.Consider the following regression output on the relationship between jaw width(in inches) of a shark (response variable) and length (in feet) of the shark (explanatory variable) for a random sample of 24 sharks. Scientists are interested in predicting a shark's jaw width from its length. Correlation coefficient: 0.8749 Estimate of sigma: 1.3757417
Parameter Estimate Std. Err. DF T-stat P-value Intercept 0.687864 1.299051 22 0.529513 0.5992 length 0.96345 0.082276 22 11.70994 <.0001 - A.
A confidence interval for the mean jaw width of newly born sharks.

- B.
A confidence interval for the slope of the regression line.

- C.
A confidence interval for the y-intercept of the regression line.

- D.
A prediction interval for the jaw width of a newly born shark.

- 71.Consider the following regression output on the relationship between jaw width(in inches) of a shark (response variable) and length (in feet) of the shark (explanatory variable) for a random sample of 24 sharks. Scientists are interested in predicting a shark's jaw width from its length. Correlation coefficient: 0.8749 Estimate of sigma: 1.3757417
Parameter Estimate Std. Err. DF T-stat P-value Intercept 0.687864 1.299051 22 0.529513 0.5992 length 0.96345 0.082276 22 11.70994 <.0001 - A.
15.1 inches

- B.
25.1 inches

- C.
35.1 inches

- D.
45.1 inches

- E.
55.1 inches

- 72.A researcher from the A researcher from the NBA randomly sampled professional basketball players and obtained information about each player's attitude toward gambling restrictions (agree, strongly agree, disagree, etch.) and the player's division (whether pacific, west, east, or south) Testing the relationship between player attitudes and player's division, a P-value of 0.027 was computed. Using alpha=0.05, the researcher decided to reject the null hypothesis. Which one of the following conclusions is most appropriate for these results.
- A.
Player's attitudes toward gambling restrictions are associated with which division they play.

- B.
Player's attitudes toward gambling restrictions are NOT associated with which division they play.

- C.
Player's attitudes toward gambling restrictions are NOT correlated with which division they play.

- D.
Player's attitudes toward gambling restrictions are linearly correlated with which division they play.

- E.
Professional basketball players are role models. Therefore they should not gamble.

- 73.What does the standard error of x-bar estimate?
- A.
The standard deviation of the sampling distribution of the sample mean.

- B.
The standard deviation of the sample mean.

- C.
The mean of the sampling distribution of the sample mean.

- D.
The standard deviation of the population.

- 74.A quality control person inspects batches of bluray discs to make inferences about the proportion p in the shipment with major defects. A batch is rejected if it can be determined that more than 5% of the batches has defects. He selects an SRS of 200 bluray discs from the thousands in a particular batch. Thirteen of the sampled bluray discs are found to have major defects. He wishes to test the following H: p=0.05 versus Ha: p > 0.05. Why can we use the standard Normal distribution to find the P-Value?
- A.
Because both np and n(1-p) are 10 or more.

- B.
Because both np and n(1-p) are 5 or more.

- C.
Because np is 10 or more.

- D.
Because n(1-p) are 10 or more.

- E.
Because bluray discs have high quality.

- 75.What is the sampling distribution of p-hat?
- A.
It is the distribution of sample proportions based on all samples of size n from a population.

- B.
It is the distribution of population proportions based on all samples of size n from a population.

- C.
It is the distribution of sample standard deviations based on all samples of size n from a population.

- D.
It is the distribution of sample standard deviations based on all samples of size n from a population.

- E.
It is the distribution of sample means based on all samples of size n from a population.

- 76.Suppose we are testing Ho: mean=70 versus Ha: mean > 70, and we obtain x-bar=64 and s=10 for a random sample of size 36. What is the value of the t test statistic?
- A.
3.6

- B.
6.3

- C.
-2.6

- D.
-3.6

- E.
-6.3

- 77.When do we declare a result to be statistically significant?
- A.
When the result has a large probability of occurring by chance.

- B.
When the result has a small probability of occurring by chance.

- C.
When it is practically significant.

- D.
When the result is meaningful.

- E.
When the result is consistent with our expectation.

- 78.Swine flu is a serious health problem. A study was conducted to see whether taking Terraflu would prevent the serious effect of swine flu. Of the 500 subjects who were diagnosed with swine flu, 280 were randomly assigned to receive the Terraflu and 220 did not receive the Terraflu. The researchers tested the hypotheses Ho: p1 = p2 versus Ha: p1 < p2 where p1 represents the proportion of those receiving the Terraflu who developed serious effect due to swine flu and p2 represents the proportion of those in the control group (no Terraflu) who deveoped serious effect due to swine flu. The data yielded a P-value of 0.336. On the basis of this P-value, can you conclude that taking Terraflu prevents serious effect of the swine flu at alpha=0.05?
- A.
Yes, because an experiment was conducted.

- B.
Yes, because the proportion of swine flu victims who received the Terraflu and developed serious effect is significantly greater than those who did not receive the Terraflu.

- C.
No, because the result is not statistically significant.

- D.
No, because the experiment did not have double blind.

- 79.The BYU Administration plans to conduct a survey among BYU single students to determine the proportion of single students who go out on a date every week. How many single students must be polled to estimate this proportion to within 0.04 with 95% confidence?
- A.
600

- B.
601

- C.
422

- D.
423

- E.
1037

- 80.In practice, if the assumption of normality of the population is not met and n < 40 , confidence levels and P-values for t procedures are approximately correct provided:
- A.
The The data has outliers.

- B.
The data is very skewed.

- C.
There are no outliers nor strong skewness in the data

- D.
Cannot be determined.

- 81.If we want to determine whether political party affiliation and opinion regarding health care reforms are related, what statistical procedure should we sue?
- A.
ANOVA

- B.
Chi-square test for independence

- C.
Correlation

- D.
Two-sample proportion z test

- E.
Two-sample t test for means

- 82.Standard deviation of the sampling distribution of p-hat.
- A.
A

- B.
B

- C.
C

- D.
D

- E.
E

- 83.Standard error of x-bar.
- A.
A

- B.
B

- C.
C

- D.
D

- E.
E

- 84.Mean of the sampling distribution of x-bar.
- A.
A

- B.
B

- C.
C

- D.
D

- E.
E

- 85.Mean of the sampling distribution of p-hat.
- A.
A

- B.
B

- C.
C

- D.
D

- E.
E

- 86.If a result is statistically significant, then either the null hypothesis is false or a type I error was committed.
- A.
True

- B.
False

- 87.We assume Ho is false whenever we perform a test of significance.
- A.
True

- B.
False

- 88.A result that is statistically significant will also be practically significant.
- A.
True

- B.
False

- 89.When n=60, the standard deviation of the sampling distribution of x-bar will be smaller than the standard deviation of the population.
- A.
True

- B.
False

- 90.The more serious the consequences of Type II error, the smaller alpha should be set.
- A.
True

- B.
False

- 91.The sampling distribution of p-hat is more spread out when n=300 than when n=150.
- A.
True

- B.
False

- 92.The mean of the theoretical sampling distribution of x-bar is always equal to the population mean.
- A.
True

- B.
False

- 93.Testing multiple null hypotheses using the same data set increases the overall probability of making a type I error.
- A.
True

- B.
False

- 94.The shape of the sampling distribution of p-hat becomes approximately Normal as n gets large.
- A.
True

- B.
False