The U.S. Census Bureau collects data on the ages of married people. Suppose that eight married couples are randomly selected and have the ages given in the following table. Determine the 80%80% confidence interval for the true mean difference between the ages of married males and married females.

Let d=(ageofhusband)(ageofwife)d=. Assume that the ages are normally distributed for the populations of both husbands and wives in the U.S.

Step 2 of 4:

Find the critical value that should be used in constructing the confidence interval. Round your answer to three decimal places.

Step 3 of 4:

Find the standard deviation of the paired differences to be used in constructing the confidence interval. Round your answer to one decimal place.

Step 4 of 4:

Construct the 80%80% confidence interval. Round your answers to one decimal place.

Husband	28	73	52	54	33	68	52	70
Wife	22	70	46	50	45	59	63	64