Question

Assume that a sample is used to estimate a population mean μμ. Find the 95% confidence interval for a sample of size 65 with a mean of 83.2 and a standard deviation of 7.7. Enter your answer as an open-interval (i.e., parentheses) accurate to 3 decimal places.

95% C.I. =

Answer 1

Solution :

Given that,

t /2,df = 1.998

Margin of error = E = t/2,df * (s /n)

= 1.998 * (7.7 / 65)

Margin of error = E = 1.908

The 95% confidence interval estimate of the population mean is,

- E < < + E

83.2 - 1.908 < < 83.2 + 1.908

81.292 < < 85.108

95% C. I. (81.292 , 85.108)