Mean 173 N 30 Variance 661 Standard deviation 26 standar

Mean = 1.73

N = 30

Variance = 6.61

Standard deviation = 2.6

standard error .47

margin of error .92

critical value .975

interval lower .81 and upper 2.65

Find the sample size you would need to take for the margin of error to be half of what was found in the confidence interval

Solution

to make margin of error half, we need to make sample size 4 times because sample size comes in square root of denominator in formula of margin of error. Thus, sample size needed is 30*4 = 120