statistics
posted by Sandra on .
4. Suppose you administered an anxiety test to a large sample of people and obtained normally distributed scores with a mean of 45 and standard deviation of 4. Do not use webcalculator to answer the following questions. Instead, you need to use the Z distribution table in Appendix A in Jackson’s book.
a. If Andrew scored 45 on this test. What is his Z score?
b. If Anna scored 30 on this test. What is her Z score?
c. If Bill’s Z score was 1.5, what is his real score on this test?
d. There are 200 students in a sample. How many of these students will have scores that fall under the score of 41?
5. The table below shows Psychology exam scores, Statistics Exam scores, and IQ scores for a random sample of students. What can you observe in the relationship between IQ and psychology, psychology and statistics, and IQ and statistics? Using a webcalculator, obtain the Pearson’s r and coefficient of determination for the following relationships.
a. Between the IQ and psychology scores
b. Between the IQ and statistics scores
c. Between the psychology scores and statistics scores.
Student number IQ Psychology Statistics
101 142 49 49
102 100 30 32
103 103 36 38
104 121 44 41
105 120 35 42
106 115 47 43
107 101 37 35
108 109 45 47
109 111 30 43
110 115 49 46
6. In a study on caffeine and stress, college students indicated how many cups of coffee they drink per day and their current stress level on a scale of 1 to 10. The table shows the survey results. Using a webcalculator, obtain the appropriate correlation coefficients.
Number of cups of coffee Stress level
3 5
2 3
4 3
6 9
5 4
1 2
7 10
3 5

4. Suppose you administered an anxiety test to a large sample of people and obtained normally distributed scores with a mean of 45 and standard deviation of 4. Do not use webcalculator to answer the following questions. Instead, you need to use the Z distribution table in Appendix A in Jackson’s book.
a. If Andrew scored 45 on this test. What is his Z score?
b. If Anna scored 30 on this test. What is her Z score?
c. If Bill’s Z score was 1.5, what is his real score on this test?
d. There are 200 students in a sample. How many of these students will have scores that fall under the score of 41?