Hello I am really struggling in these practice questions, need to double check if mine are right. please help me

1.

The regression equation isy = 79.80x 7.42

If the coefficient of determination is r2=0.6704, then what is the coefficient of correlation is which one from the bottom:

a. 79.80

b. 0.8188

c. -0.8188

d. 0.3188

e. -0.3188

2.

This symbol represents the probability of what at:

a. Rejecting a false null hypothesis

b. Failing to reject a true alternative hypothesis

c. Rejecting a true null hypothesis

d. Failing to reject a false null hypothesis

e. Failing to reject a true null hypothesis

3.

A sales team claims that their daily sales in their department exceed that of their competition by more than27 sales per day so. The null hypothesisH0 can be mathematically expressed as what from the below?

a. 2 1 27

b. 2127

c. 21=27

e. 2-1-27

f. 21<27

4.

A researcher has been wanting to test the hypothesis that childhood exposure to advertising exceeds 111 ads per day. Randomly selecting 59 days, these people calculated the sample mean, and they also know the population standard deviation. The researchers should use which following distribution:

a. Chi-squared distribution

b. Binomial distribution

c. Student-t distribution

d. normal (z) distribution

e. She cannot perform the test as the population standard deviation is not available

5.

A researcher is wanting to find the estimate the mean exposure to this certain type of internet advertisement. Initially they found a 99% confidence interval, and then, with all other factors the same, they decreased the confidence level to 90%. As a final result...

a. the confidence interval will become narrower

b. the confidence interval will become wider

c. the confidence interval will not change

d. the confidence interval may get wider or narrower

e. none of the above