10 If a population proportion is believed to be 0.43, how many items must be sampled to ensure that the sampling distribution of the sample proportionwill be approximately normal?

11 A researcher studying public opinion of proposed Social Security changes obtains a simple random sample of 30 adult Americans and asks them whether or not they support the proposed changes. To say that the distribution of the sample proportion of adults who respond yes, is approximately normal,how many moreadult Americans does the researcher need to sample if 43% of all adult American support the changes?

12A pollster wishes to estimate the number of left-handed scientists. What is the minimum sample size needed in order to be 90% confident that the estimate will be within 3 percentage points? A previous study indicated that the proportion of left-handed scientists is 14%.

Remember to always round up when determining the sample size. The z-score used should be rounded to 3 decimal places.

13A study of 22 car owners showed that theirmeanrepair bill was $150 with a standard deviation of $8.00.Construct a 90% confidence interval for the population mean. Assume the population has a normal distribution. Do not include the $ in your responses.

(lower bound, upper bound)

14Many colleges are encouraged to offer tuition waivers for their employees. However, one watch-groupclaims that less than 45%of colleges in the U.S. offer tuition waivers for their employees. There are currently 5,300 colleges in the U.S. Two hundred colleges were randomly selected and asked if they offer tuition waivers for their employees. Only 65 colleges stated that they offered tuition waivers for their employees. Use a 0.01 level of significanceto test the watch-group's claim.

Round all answers to 4 decimal places.

Test Statistic =

p-value =

Reject the null hypothesis (yes/no)

Is there sufficient evidence to support the watch-group's claim that less than 45% of colleges offer tuition waivers to their employees (yes/no)?

15 Astatisticsinstructor is interested in determining whether or not a review session improvedstudent performance on the final exam. The review session was administered to a sample of students (n=32) in an attempt to determine if this has a positive effect on exam performance. Based on information gathered in previous semesters, the population mean for the final exam is 75.2. The sample mean obtained from the 32 students is 80 with a sample standard deviation of 12.

Use a 0.01 significance level to test the instructor's claim that the review session improved student performance on the final exam.

Round all answers to 3 decimal places.

Test Statistic =

p-value =

Reject the null hypothesis (yes/no)

Is there sufficient evidence to support the instructors claim that the review session improved student performance on the final exam (yes/no)?

16 Time magazine reported the result of a telephone poll of 800 adult Americans. The question posed of the Americans who were surveyed was: "Should the federal tax on cigarettes be raised to pay for health care reform?" The results of the survey were:

Data Table
	Those responding yes	Sample Size
Non-Smokers	351	605
Smokers	91	195

At the= 0.05 level, test the claim that non-smokers and smokers differ significantly with respect to their opinions about healthcare reform funding.

Round all answers to 3 decimal places.

Test Statistic =

p-value =

Reject the null hypothesis (yes/no)

Is there sufficient evidence that there is a significant difference in the proportions of the two groups, non-smokers and smokers (yes/no)?

17 Time magazine reported the result of a telephone poll of 800 adult Americans. The question posed of the Americans who were surveyed was: "Should the federal tax on cigarettes be raised to pay for health care reform?" The results of the survey were:

Data Table
	Those responding yes	Sample Size
Non-Smokers	351	605
Smokers	91	195

Construct and interpret a 95% confidence interval for p1p2

Round all answers to 3 decimal places.

Lower Bound

Upper Bound

Is zero contained in the interval? (yes/no)

Is there sufficient evidence that there is a significant difference in the proportions of the two groups, non-smokers and smokers (yes/no)?