Math Statistics

HW 8 - Math 10 For the following questions, State Ho and Ha and choose the correct model from this list:

a) One population, Z test for mean b) One population, t test for mean c) One population, Z test of proportion d) One population, Chi-square test of variance

e) Z-test: comparing two independent population means f) t-test: independent samples, two population pooled variance. g) t-test: independent samples, two population unequal variance. h) t-test: dependent sampling, matched pairs

1. You want to support the claim that male bass singers are taller than male tenor singers. 20 singers of each type will be sampled. Assume that the population variances are not equal for these two groups.

2. You want to reject the claim that no more than 10% of students will suffer financial hardship if tuition increased. 400 students will be sampled.

3. An investor wants to reject the claim that the standard deviation for mutual fund portfolios is no more than 10. A total of 31 mutual fund portfolios will be sampled.

4. A study claims people now spend, on average, more time on the Internet than they do watching television. 200 people will be asked how much time they spent on the TV and on the Internet. You want to support this claim.

5. Is there a difference in quality between vegetables bought at farmers markets and vegetables bought at a high end grocer? Test this claim by sampling random vegetables from 20 farmers markets and 20 high end grocers. An F-test shows that population variances are equal for these two groups.

6. A study claims the average age for a community college student is over 27. You want to support this claim and sample 20 students.

7. A community college district compared the number of hours students worked at an outside job at its two colleges. Design and run a test to determine if there is a significant difference in hours worked by students at the 2 colleges. Use a 1% level of significance for this test. Assume population variances are equal.

(a) (DESIGN) State your Hypothesis

(e) (DATA) Conduct the test and circle your decision

Correct p-value _____________

Reject Ho Fail to Reject Ho

(f) (CONCLUSION) State your overall conclusion in language that is clear, relates to the original problem and is consistent with your decision.

(b) (DESIGN) State Significance Level of the test and explain Type I error.

(c) (DESIGN) Determine the statistical model (test statistic) Explain your reasoning.

(d) DESIGN) Determine decision rule (p-value method)