Last year, a study showed that the average ATM cash withdrawal took 65 seconds with a standard deviation of 10 seconds.

The study is to be repeated this year, but we need to determine the required sample size (n). Then, you will use a random sample from this year to construct a confidence interval for the average (mean) time it takes to withdraw cash from an ATM.

For the confidence level (1 - α) = 0.95, the critical value (CV) is

Select one:

a. 1.96

b. 1.64

c. 1.28

d. 2.58

How large a sample (rounded up) would be needed to estimate this year's mean with 95% confidence and a margin of error of 4 seconds? Use the standard deviation from last year study as the population standard deviation (σ).

Select one:

a. 25

b. 17

c. 11

d. 42

How large a sample (rounded up) would be needed to estimate this year's mean with a 95% confidence and a margin of error of 2 seconds? Use last year's standard deviation as the population standard deviation (σ).

Select one:

a. 97

b. 68

c. 41

d. 167

For the confidence level (1-α) = 0.99, the critical value (CV) is

Select one:

a. 2.58

b. 2.33

c. 1.28

d. 1.96

How large a sample (rounded up) would be needed to estimate this year's mean with a 99% confidence and a margin of error (ME) of 4 seconds? Use the standard deviation from last year as the population standard deviation (σ).

Select one:

a. 42

b. 34

c. 167

d. 97