22. SAT scores are normally distributed. Mary\'s calculated z-score on the SAT i
ID: 3069383 • Letter: 2
Question
22. SAT scores are normally distributed. Mary's calculated z-score on the SAT is -3. Which of the following is the best interpretation of Mary's z-score?
Mary's SAT score is 3 standard deviations below the average SAT score.
Mary missed three questions on the SAT.
Of those taking the SAT, 3% scored lower than Mary.
Mary's SAT score is three times below the average SAT score.
Mary's SAT score is 3 points below the average SAT score.
23. Provided below is the distribution of exam scores from an introductory statistics course. What would be the most appropriate measure of center for this distribution?
89 89 83 69 80 25 67 88 94 64
a.interquartile range (IQR)
b.mean
c.standard deviation
d.median
24. For a particular set of data, the mean is much larger than the median. Which one of the following statements is most consistent with this information?
The distribution of the data is symmetric.
The distribution of the data is skewed right.
"Mean smaller than the median" does not give any information about the shape of the distribution.
The distribution of the data is skewed left.
25. Which one of the following scenarios allows a cause-and-effect conclusion about the relationship between exercise and systolic blood pressure for men?
a. Take a simple random sample of 100 men. Ask them if they exercise more than 3 hours per week and measure their systolic blood pressure. Divide them into two groups based on whether they exercise more than three hours. Compare the mean systolic blood pressure for the two groups using a two sample t test.
b. Measure the systolic blood pressure of a randomly selected group of male Stat 121 students before and after taking the Stat final exam. Do a matched pairs t test on the differences in systolic blood pressure.
c. Randomly allocate 50 males to each of two groups. Require the men in one group to exercise 5 hours per week and the men in the other group to exercise 1 hour per week. After 6 weeks, measure their systolic blood pressure. Compare the mean systolic blood pressure for the two groups using a two sample t test.
d. Take a simple random sample of 100 men. Each man was asked the number of hours exercised per week. A nurse measured the systolic blood pressure of each man in the sample. Find the least squares regression line relating systolic blood pressure to hours of exercise.
Explanation / Answer
22) A z-score of -3 interprets that Mary's score is 3 standard deviations below the average score.
23) Here, the distribution contains outlier and hence Median will be the best measure of center for this distribution.
24) For mean larger than median, the distribution of the data is skewed right.
25) Option (d) is the correct answer.
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