Question

Suppose the following data are selected randomly from a population of normally distributed values.

41 51 43 48 43 57 54 39 40 48 45 39 41

Construct a 95% confidence interval to estimate the population mean.

(Round the intermediate values to 2 decimal places. Round your answers to 2 decimal places.)

Answer 1

Mean ( X Bar ) = 45.31

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Sample Standard Deviation (s ) = 5.88

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At 95 % Confidence level t is = 2.1788 ( By using table ).

At 95 % , confidence interval for mean is,

X bar = 45.31 , t = 2.1788 , s = 5.88 , n = 13.

Confidence interval at 95 % is = ( 41.76 , 48.86 )