Assignment 8: Single Sample Inferences
Due at start of class on 10 March, 2006. Name:
Email Address:

Each question is worth one half of one point unless otherwise indicated.

The mean IQ is 100 with a standard deviation of 15. The mean IQ of a random sample of 21 UD students is 115. Is the IQ of UD students likely to be different from the average IQ of the population?

1. What is the alternative hypothesis? (Use u for μ; since you cannot subscript, just type the subscripted information normally.)
2. What is the null hypothesis?
3. Is this a one-tailed or two-tailed hypothesis? One Tailed Two Tailed
4. What alpha level will you use?
5. Which type of statistic will you calculate?
1. Z-score
2. t-test
6. What is the value of the statistic that you calculated?
7. If appropriate, what is the degrees of freedom?
8. What is the value of the critical statistic (from a table.)
9. Based on the calculated statistic and the critical statistic, what conclusion will you make?
1. Accept H0
2. Reject H0
3. Accept H1
4. Fail to reject H0
10. Based on the hypothesis test, is the mean IQ of UD students likely to be different from the average IQ of the population?
1. Probably Yes
2. Probably No
3. The hypothesis test cannot answer this question.

Assume that the mean life span is 74.9 years. The mean life span of 24 individuals who owned cats was 79.3 years, with a standard deviation of 5.7 years. Do owners of cats live longer than the population?

11. What is the alternative hypothesis? (Use u for mu; since you cannot subscript, just type the subscripted information normally.)
12. What is the null hypothesis?
13. Is this a one-tailed or two-tailed hypothesis? One Tailed Two Tailed
14. What alpha (α) level will you use?
15. Which type of statistic will you calculate?
1. Z-score
2. t-test
16. What is the value of the statistic that you calculated?
17. If appropriate, what is the degrees of freedom?
18. What is the value of the critical statistic (from a table.)
19. Based on the calculated statistic and the critical statistic, what conclusion will you make?
1. Accept H0
2. Reject H0
3. Accept H1
4. Fail to reject H0
20. Based on the hypothesis test, do owners of cats live longer than the population?
1. Probably Yes
2. Probably No
3. The hypothesis test cannot answer this question.