Question

Your class has been given a test to assess educational experience. The mean on the test was 74 and the standard deviation was 10. Assuming a normal distribution, use this information and the standard normal table to answer questions 12-15. You must show all work to receive credit. Round to 3 decimal places throughout.

12. What percentage of students scored between 77 and 86? (6 points)

13. What percentage of students scored between 67 and 91? (6 points)

14. What percentage of students scored below 61? (6 points)

15. What raw score would a student have to achieve to be in the bottom 46% of test-takers? (6 points)

A random sample of 429 college students was interviewed about campus life. Use this information to answer question 16. You must show all work to receive credit. Round to 3 decimal places throughout.

16. They reported that they spent an average of $178 on textbooks during the previous semester. If the sample standard deviation for these data is $16, calculate and interpret a 99% confidence interval to estimate true average cost of textbooks. (6 points)

A random sample of 1,496 respondents was questioned about a number of issues. Use this information to answer question 17. You must show all work to receive credit. Round to 3 decimal places throughout.

17. 25% of students agreed with the statement, “Marijuana should be legalized.” Calculate and interpret a 95% confidence interval around this percentage. (6 points)

18. There is an important relationship between the standard normal distribution and confidence levels. Demonstrate your understanding of this relationship by identifying the z score associated with a 94% level of confidence. This question does not require you to use the information about the 1,496 respondents provided above. (5 points)

Answer 1