A simple random sample of 40 items resulted in a sample mean of 60. The population standard deviation is σ =20 .
a.
Compute the 95% confidence interval for the population mean. Round
your answers to one decimal place.
( , )
b.
Assume that the same sample mean was obtained from a sample of 130
items. Provide a 95% confidence interval for the population mean.
Round your answers to two decimal places.
( , )
Solution:-
a) 95% confidence interval for the population mean is
C.I = (53.80, 66.20).
C.I = 60 + 1.96*3.16228
C.I = 60 + 6.1981
C.I = (53.802 , 66.198)
b) 95% confidence interval for the population mean is C.I = (56.56, 63.44)
C.I = 60 + 1.96*1.75412
C.I = 60 + 3.4381
C.I = (56.562, 63.438)
A simple random sample of 40 items resulted in a sample mean of 60. The population...
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