Please explain these, 1) From a random sample of 58 businesses, it is found that the mean time the owner spends on administrative issues each week is...

Please explain these,

1) From a random sample of 58 businesses, it is found that the mean time the owner spends on administrative issues each week is 21.69 with a population standard deviation of 3.54. What is the 95% confidence interval for the amount of time spent on administrative issues?

(21.78, 22.60)

(20.71, 22.67)

(19.24, 24.14)

(20.93, 22.46)

2) If a confidence interval is given from 45.82 up to 55.90 and the mean is known to be 50.86, what is the margin of error?

5.04

10.08

2.52

45.82

3)The 95% confidence interval for these parts is 56.98 to 57.05 under normal operations. A systematic sample is taken from the manufacturing line to determine if the production process is still within acceptable levels. The mean of the sample is 56.96. What should be done about the production line?

Keep the line operating as it is close to the confidence interval

Stop the line as it is close to the confidence interval

Keep the line operating as it is outside the confidence interval

Stop the line as it is outside the confidence interval

4) What is the 99% confidence interval for a sample of 36 seat belts that have a mean length of 85.6 inches long and a population standard deviation of 2.5 inches?

(80.6, 90.6)

(83.1, 88.1)

(84.5, 86.7)

(84.4, 86.8)