Stattetics Sample Final Exam

94 Questions | Total Attempts: 1295

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Stattetics Sample Final Exam

Sample Final Exam


Questions and Answers
  • 1. 
    A researcher wanted to estimate the average amount of money spent per semester on books by BYU students. An SRS of 100 BYU students were selected. They visited the addresses during the Summer term and had those students who were at home fill out a confidential questionnaire. This procedure is      
    • 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. 
    Which of the following five statements about the correlation coefficient, r, is true?
    • 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. 
    If the null hypothesis is true, a statistically significant result
    • 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 Based on these data, which of the following statements is most correct?
    • 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. 
    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 all the assumptions are met?
    • 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 The slope of the least-squares line, b, is equal to 1.4. Which statement is the best interpretation of b?
    • 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.