Question

In a random sample of

35

?refrigerators, the mean repair cost was

?$117.00

and the population standard deviation is

?$16.30

Construct a

90?%

confidence interval for the population mean repair cost. Interpret the results.

Answer 1

Solution:-

90?% confidence interval for the population mean repair cost is C.I = (112.47 , 121.53).

n = 35, Mean = 117, S.D = 16.30

C.I = 117 + 1.645 × 2.7552

C.I = 117 + 4.5323

C.I = (112.47 , 121.53)