60 Questions
| Total Attempts: 890

Test1 sample for Stats221 class.

Questions and Answers

- 1.
- A.
More points are scored in the 3-pt line than steals.

- B.
About 70% of the points come from Free throws and 2-point shots.

- C.
Most points come from the 2-point shots.

- D.
The distribution is skewed to the left.

- 2.Consider the following 5-number summary of 120 NBA teams scores: Which of the following observations in the data set would be called a suspected outlier?
- A.
An observation between 85 and 100.

- B.
An observation less than 125.

- C.
An observation between 70 to 100.

- D.
An observation greater than 145

- E.
E. There are no suspected outliers in this data set.

- 3.Here are the boxplots of Stats221 Final scores for Provo and Salt Lake Campus: T F Both distributions are skewed to the left.
- A.
True

- B.
False

- 4.Here are the boxplots of Stats221 Final scores for Provo and Salt Lake Campus: 1. T F Fifty percent of the SLC students scored approximately between 65 and 85.
- A.
True

- B.
False

- 5.Here are the boxplots of Stats221 Final scores for Provo and Salt Lake Campus: 1. T F Scores exhibit less spread for Provo than SLC.
- A.
True

- B.
False

- 6.Here are the boxplots of Stats221 Final scores for Provo and Salt Lake Campus: The interquartile range for SLC is about 20.
- A.
True

- B.
False

- 7.Here are the boxplots of Stats221 Final scores for Provo and Salt Lake Campus: The proportion of Provo scoring between 62 to 82 is greater than the proportion of SLC scoring between 65 to 85.
- A.
True

- B.
False

- 8.Here are the boxplots of Stats221 Final scores for Provo and Salt Lake Campus: The mean is greater than the median for scores in Provo.
- A.
True

- B.
False

- 9.Here are the boxplots of Stats221 Final scores for Provo and Salt Lake Campus: The proportion of SLC scoring below 85 is larger than the proportion of Provo scoring below 85.
- A.
True

- B.
False

- 10.Which of the following graphical displays can be drawn using only the 5 number summary?
- A.
Scatterplot

- B.
Bar graph

- C.
Stemplot

- D.
Histogram

- E.
Boxplot

- 11.Which one of the following is a FALSE statement about statistical problem solving?
- A.
Each step in statistical problem solving can be manipulated either innocently or deliberately to influence peopleâ€™s opinion.

- B.
Determining what should be measured is an important part of question formulation.

- C.
Subjects should always be chosen without human subjectivity or bias.

- D.
Numbers should always be reported in context

- E.
Giving measure of confidence is not necessary when reporting results of statistical inference.

- 12.What does the standard deviation of a distribution measure?
- A.
Shape

- B.
Spread

- C.
Center

- D.
Skewness

- 13.Coach Sloan is testing a new method of shooting free throws and plans to randomly assign 20 players to the new method 25 players to the traditional method. The mean percentage of free throws will then be compared between these two groups. What type of study is this?
- A.
An observational study

- B.
A simple random sample

- C.
A matched pairs experiment.

- D.
A completely randomized experiment.

- E.
A randomized block experiment.

- 14.
- A.
0.0668

- B.
0.3085

- C.
0.4325

- D.
0.6915

- E.
0.4984

- 15.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. A critic of the research project argued that the results lack believability because some single students do not live in BYU dorms. This critic is arguing that the study suffers from
- A.
Response bias due to question wording.

- B.
Response bias due to interviewer effect.

- C.
Under-coverage.

- D.
Non-response bias.

- 16.
- Which of the following constitutes a multistage sample 28 elementary school students in the Provo school district?

- A.
Obtain a list of all elementary school students in the Provo school district area; assign consecutive numbers to the students on the list; use a random number table to select 28 students from the list.

- B.
Obtain a list of all elementary school students from each of the 14 elementary schools in the Provo district; use a random number table to select 2 students from each school.

- C.
Randomly select 4 elementary schools in the Provo district; from each of the selected schools randomly select one grade class; from each of the selected classes randomly select 7 students.

- D.
Randomly select 4 schools in the Provo district, from each of the selected schools randomly select one grade class; from each of the selected classes randomly select 7 students.

- 17.The mean points of NBA players is 20 points a game with a standard deviation of 5. The mean points for the PBA (Philippine Basketball Association) is 30 with a standard deviation of 10. Wesley scores 22 points a game for the NBA while Doria scores 31 points a game for the PBA. Who has scores the highest in their league?
- A.
Wesley

- B.
Doria

- C.
They have equal scores

- D.
Cannot be determined from given information.

- 18.When should we use a probability sample?
- A.
So the sample can be used to make inferences about the population.

- B.
Because it is more convenient to use than other types of samples.

- C.
So that bias will be eliminated completely from the sample.

- D.
So that the sample will perfectly represent the population.

- E.
So that sampling variability will be removed.

- 19.A researcher wants to know whether clean air filter improves gas mileage. 10 vehicles were randomly selected. For each vehicle, a coin is tossed. If it is heads, a clean air filter is installed first in the vehicle and the average mileage is computed. After the testing, a dirty air filter is installed and the average mileage is computed. If it is tails, then a dirty air filter is installed first and then a clean air filter is installed next. This study is an example of
- A.
A completely randomized experiment

- B.
A randomized block experiment

- C.
A matched pairs experiment

- D.
An observational study

- E.
A multi-stage sample

- 20.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.
Jeremiahâ€™s score is only 2.5

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

- C.
Jeremiahâ€™s scoring is 2.5 times the average scoring in the league.

- D.
Jeremiahâ€™s scoring is 2.5 standard deviations above the average scoring in the league.

- E.
Jeremiahâ€™s scoring is 2.5 points above the average scoring in the league.

- 21.Coach Sloan is wants to know how different feet positions affect shooting field goal percentage. He randomly assigns 30 players to 3 different feet positions. He compares the field goal percentages among the three groups. This study is an example of
- A.
A completely randomized experiment

- B.
A randomized block experiment

- C.
A matched pairs experiment

- D.
An observational study

- E.
A multi-stage sample

- 22.A study was conducted using growing rats to examine the effect of jumping height on the strength of bones. Thirty rats were randomly allocated into groups. The first group of rats did low jumps of 30 cm. And the second group of rats did high jumps of 60 cm. After 8 weeks of 10 jumps per day, 5 days per week, the bone density of the rats was measured in mg/cm
^{3}. What is the explanatory variable?- A.
Growing rats

- B.
Height of jump

- C.
Bone density as measured in mg/cubic cm.

- D.
Age of rat.

- 23.
- A.
28

- B.
44

- C.
53

- D.
56

- E.
60

- 24.Refer to the histogram below. It is a frequency histogram of Religiosity among 226 randomly selected college students. What is the rough estimate of the standard deviation of the above histogram?
- A.
1

- B.
3

- C.
5

- D.
7

- E.
9

- 25.Refer to the histogram below. It is a frequency histogram of Religiosity among 226 randomly selected college students. How does the mean and median compared for this distribution?
- A.
The mean is less than the median

- B.
The mean is equal to the median

- C.
The mean is greater than the median

- D.
Cannot be determined

- 26.Refer to the histogram below. It is a frequency histogram of Religiosity among 226 randomly selected college students. What is the appropriate measure of spread for the distribution of religiosity in the above problem?
- A.
Mean religiosity

- B.
Median religiosity

- C.
Standard deviation of religiosity

- D.
IQR of religiosity

- 27.Refer to the histogram below. It is a frequency histogram of Religiosity among 226 randomly selected college students. What is the most reasonable value for Q1, the first quartile, of the 226 religiosity values in the previous question?
- A.
28

- B.
44

- C.
53

- D.
56

- E.
60

- 28.Refer to the histogram below. It is a frequency histogram of Religiosity among 226 randomly selected college students. Why does the histogram above represent a distribution?
- A.
Because the values of Religiosity is from 22 to 62.

- B.
Because it shows how Religiosity is a lurking variable

- C.
Because values for frequencies are given on the horizontal axis and the bars represent their Religiosity

- D.
Because values for Religiosity are given on the horizontal axis and the bars represent their frequencies.

- 29.Church League scoring follows a normal distribution with 16% of the scores greater than 41.4 and 16% less than 38.8. What is the standard deviation for these scores?
- A.
1.3

- B.
2.3

- C.
3.4

- D.
4.3

- 30.
- 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.

- 31.A Sunday school teacher records the attendance for the first 10 meetings. A record of the attendance is shown below. 42 46 30 43 43 8 41 40 43 44 Considering the distribution of the data, which value best summarizes the attendance at the Sunday School meetings?
- A.
39.5

- B.
42.5

- C.
43.5

- D.
46.5

- 32.Below is a back-to-back stemplots of the number of A’s in a stats221 class for Provo an SLC for the last 33 semesters: Which of the following is most correct?
- A.
Provo has a higher average and a smaller variability.

- B.
Provo has a higher average, but SLC has s smaller variability.

- C.
SLC has a higher average and higher variability.

- D.
SLC has s higher average, but smaller variability.

- 33.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.
Smaller than

- B.
The same

- C.
Larger than

- D.
Cannot be determined from the information given.

- 34.To investigate the effects of playing basketball, 100 men in the 40-50 age range who play basketball were located. Also, 100 men of the same age and weight ranges, who had never played basketball, were located. The incidence of constipation was compared between the two groups. What kind of study is this?
- A.
A multi-staged sample

- B.
A simple random sample

- C.
A completely randomized experiment

- D.
A matched pairs experiment

- E.
An observational study

- 35.The NBA scores are normally distributed. Approximately what percent of these scores will fall between one standard deviation below the mean and two standard deviations above the mean?
- A.
48%

- B.
61%

- C.
68%

- D.
82%

- E.
95%

- 36.What do we mean when the difference between two treatments, in a comparative experiment, are statistically significant?
- A.
Very close to what was expected

- B.
So large that there a mistake must have been committed

- C.
Due to chance or sampling error

- D.
Too large to claim that the difference is due to chance

- 37.A study measured the Forced Expiratory Volume (FEV, a measure of lung capacity for which higher numbers mean more lung capacity) on several school children ranging in age from 6 to 18. The study also asked the children if the are or have been smokers. Surprisingly the average FEV computed for smokers is higher than the average FEV for non-smokers. Which of the following should we consider when interpreting results from this study:
- A.
Since this is an observational study, we can conclude that smoking causes an increase in FEV

- B.
Age and height might be lurking variables because older kids will have larger lungs and will be more likely to smoke.

- C.
Since this is a designed experiment, we can conclude that smoking causes an increase in FEV

- D.
The study results are different from what was expected and therefore we should conclude that there is no relationship between smoking and FEV.

- E.
Children should not smoke and therefore the study must be invalid.

- 38.The Statistics Department reported that there was a total of 3,215 Stats221 classes that have been offered with a mean enrollment of 55 and a standard deviation of 15. A random sample of 200 Stats221 classes had a mean enrollment of 51 and a standard deviation of 12. What symbols are commonly used to denote these values?
- A.
A

- B.
B

- C.
C

- D.
D

- 39.
- In order to assess opinions of BYU single students about the stated curfew regulation, a random sample of BYU single students were selected from each Singles Ward in BYU. What type of sample is this?

- A.
Simple random Sample

- B.
Stratified random sample

- C.
Multistage sample

- D.
Completely Randomized experiment

- E.
Randomized Block Design

- 40.Which is the BEST graphical method for presenting the distribution of a categorical variable?
- A.
Histogram

- B.
Stemplot

- C.
Boxplot

- D.
Bar graph

- E.
Pie chart

- 41.Which interval below will contains the most data?
- A.
A

- B.
B

- C.
C

- D.
D

- E.
E

- 42.A Portfolio Manger is interested in studying the effects of some variables on stock returns. Which of the following variables is quantitative?
- A.
Zip code

- B.
Area code

- C.
Industry type

- D.
Cash Flow

- 43.Which density curve has the smallest standard deviation?
- A.
A

- B.
B

- C.
C

- 44.Which of the following is a benefit of a randomized block design compared to a completely randomized design?
- A.
Blocking can be used as a substitute for double blinding.

- B.
Blocking reduces chance variation by removing variation associated with the blocking variable.

- C.
Blocking removes bias created by not randomly allocating individuals to the treatments.

- D.
Blocking can be used instead of reproducing the entire experiment in order to estimate chance variation.

- 45.Given a histogram, how will you approximate the standard deviation?
- A.
Use the standard deviation formula.

- B.
Range divide by 2

- C.
Range divide by 4.

- D.
Range divide by 6

- E.
Cannot be computed.

- 46.A Sunday school teacher records the attendance for the first 10 meetings. A record of the attendance is shown below. What is the Interquartile Range (IQR)? 42 46 30 43 43 8 41 40 43 44
- A.
38

- B.
42

- C.
43.5

- D.
35

- E.
3

- 47.A Sunday school teacher records the attendance for the first 10 meetings. A record of the attendance is shown below. Which measure of center best summarizes the attendance at the Sunday School class? 42 46 30 43 43 8 41 40 43 44
- A.
35

- B.
43

- C.
43.5

- D.
41.5

- E.
42.5

- 48.When looking at the histogram below, how do the mean and median compare?
- A.
Cannot be determined.

- B.
The mean is greater than the median.

- C.
The mean is equal to the median.

- D.
The mean is less than the median.

- 49.A financial adviser told you that it is better to invest your money in the stock market than putting it in the bank. Assume that the distribution of stock returns is normal with mean 10.05% and standard deviation of 12.12% per year. You want to invest in a strategy that results in the highest 4% of the returns. Thus you will select an investment with return higher than ________ .
- A.
20.1

- B.
25.7

- C.
31.26

- D.
40.26

- E.
Cannot be calculated.

- 50.A financial adviser told you that it is better to invest your money in the stock market than putting it in the bank. Assume that the distribution of stock returns is normal with mean 10.05% and standard deviation of 12.12% per year. Find the proportion of people who invested in the stock market that get between 8 to 11% return on a typical year.
- A.
0.0994

- B.
0.0735

- C.
0.3651

- D.
0.6349

- E.
Cannot be calculated.

- 51.Consider the following histogram of religiosity of college students. What is the appropriate measure of spread for this distribution?
- A.
Mean religiosity

- B.
Median religiosity

- C.
Standard deviation of religiosity

- D.
Interquartile range of religiosity

- E.
Range

- 52.There are three portfolio managers in a room who managed money for 10, 15, and 20 years. If a portfolio manager who managed money for 15 years enters the room, what will happen to the mean and standard deviation of the years managing money?
- A.
The mean and standard deviation will increase.

- B.
The mean and standard deviation will decrease.

- C.
The mean and standard deviation will stay the same.

- D.
The mean will stay the same but standard deviation will decrease.

- E.
The mean will stay the same but standard deviation will increase.

- 53.A financial adviser told you that it is better to invest your money in the stock market than putting it in the bank. Assume that the distribution of stock returns is normal with mean 10.05% and standard deviation of 12.12% per year. Find the proportion of people who invested in the stock market that get more than 20% return on a typical year.
- A.
0.0994

- B.
0.0735

- C.
0.2061

- D.
0.7939

- E.
None of the above.

- 54.A researcher wants to determine if the singles students at BYU would be interested in participating in the compatibility service to be provided by the BYU student services. From a list of BYU single students, the researcher contacted an SRS of 200 and asked them if they would be interested in participating in the compatibility service to be provided by the BYU student services. A total of 50 students said yes. What is the sample in this survey?
- A.
All BYU single students

- B.
All students in BYU.

- C.
The 200 students who were contacted.

- D.
The 50 respondents who said yes.

- 55.A researcher wants to determine if the singles students at BYU would be interested in participating in the compatibility service to be provided by the BYU student services. From a list of BYU single students, the researcher selects an SRS of 200 and mails a brief questionnaire addressed to a single student address. A total of 50 questionnaires are returned. What is the chance that all 200 BYU single students came from BYU 215 Ward ?
- A.
Exactly zero because an SRS will contain addresses from all BYU singles students from different wards

- B.
Reasonably larger due to sampling variability.

- C.
200 divided by the size of the population of BYU single students.

- D.
The same as for any other set of 200 BYU single students.

- E.
Cannot be computed.

- 56.A study was conducted using growing rats to examine the effect of jumping height on the strength of bones. Thirty rats were randomly allocated into groups. The first group of rats did low jumps of 30 cm. And the second group of rats did high jumps of 60 cm. After 8 weeks of 10 jumps per day, 5 days per week, the bone density of the rats was measured in mg/cm
^{3}. What is the response variable?- A.
Growing rats

- B.
Height of jump

- C.
Bone density

- D.
Age of rat

- E.
None of the above.

- 57.
- A.
No, because the study is an observational study.

- B.
No, because of possible bias dues to lack of placebo.

- C.
No, because the study was only performed once.

- D.
Yes, because the study is a valid experiment.

- E.
Yes, because the study is double blind.

- 58.
- There are five BYU basketball players in a room, ages 18, 19, 20, 21, 22. If two players, ages 18 and 22, enter the room, what will happen to the mean and standard deviation?

- A.
The mean age will stay the same but the standard deviation will increase.

- B.
The mean age will stay the same but the standard deviation will decrease.

- C.
The mean age and standard deviation will stay the same.

- D.
The mean age and standard deviation will increase.

- E.
The mean will decrease and the standard deviation will increase.

- 59.According to the NBA rules, a basketball is supposed to weigh between 20 to 22 ounces. Basketball produced by Spalding on one production line have a mean 21.3 ounces and a standard deviation of 0.3 ounces. The weights of these basketball are approximately Normally distributed. What proportion of the ball produced on this production line meet the standard weight of the balls?
- A.
0.9901

- B.
0.0406

- C.
0.9954

- D.
0.9945

- E.
None of the above.

- 60.According to the NBA rules, a basketball is supposed to weigh between 20 to 22 ounces. Basketball produced by Spalding on one production line have a mean 21.3 ounces and a standard deviation of 0.3 ounces. The weights of these basketball are approximately Normally distributed. Above what weight are the 90% of the basketball balls?
- A.
21.92

- B.
20.92

- C.
22.92

- D.
None of the above.