Use the values in the table below, which represent the heights, in inches, of 36 randomly-selected students enrolled in Qmeth201, this semester, to answer/complete Parts a through c:

68 72 62 70 70 72 70 69 71 64 71 68 62 65 65 63 67 62 64 67 63 70 65 63 69 77 66 74 71 69 77 77 65 70 71 60

a. Estimate, with 90 percent confidence, the proportion of all students enrolled in Qmeth201, this semester, who are at least 70 inches tall.

b. How would the width of the interval in Part a change if you wanted to be 99 percent confident, holding all other values/ideas constant?

c. How would the width of the interval in Part a change if the sample size equaled 49, holding all other values/ideas constant?