1.Simple random samples of adults ages 18- 24 years and adults ages 25-30 years are obtained. How much each adult spent on interest purchases for a month was recorded with the results listed below:

18- 24 year

n = 31

Mean =$52.00

S.d= $21.30

25-30 years

n = 35

Mean = $45.49

S.d = $13.19

a) Construct a 95% confidence interval for the difference in mean amount spent.

Point Estimate:

Margin Error:

95% confidence interval :

b) Does your answer to part a) suggest that there is a significant difference between the average amount spent on internet purchases between the two groups? Why or why not?

2. In 2016 a national publication randomly polled 1003 people and 592 said that they have never hesitated to shake hands because of a fear of germs.

a) Construct a 99% confidence interval for the population proportion of people who never hesitated to shake hands because of a fear of germs.

Point Estimate:

Margin Error:

Final confidence interval answer:

b) Does this poll seem to give good evidence that the majority of people say that they do not hesitate to shake hands because they fear germs? Why or why not?

How large of a new sample would be needed to obtain a margin of error of +/- 2% if the sample stated above has been determined to be obtained on behalf of a hand sanitizer company and therefore unreliable because of possible bias? (Still assume 99% confidence.)