Bob Nale would like to determine the mean number of gallons of gasoline sold to his...

Bob Nale would like to determine the mean number of gallons of gasoline sold to his customers. Assume the number gallons of gasoline sold is 2 gallons. From his records, he selects 64 samples and finds the mean is 9 gallons. Find the 95% confidence interval for the population mean.

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Expert Solution

point estimate , x̅ = 9

σ =2

n = 64

Level of Significance ,    α =    0.05
'   '   '
z value=   z α/2=   1.9600   [Excel formula =NORMSINV(α/2) ]

Standard Error , SE = σ/√n =   2.000   / √   64   =   0.2500
margin of error, E=Z*SE =   1.9600   *   0.250   =   0.490

confidence interval is
Interval Lower Limit = x̅ - E =    9.00   -   0.490   =   8.5100
Interval Upper Limit = x̅ + E =    9.00   -   0.490   =   9.4900
95%   confidence interval is (   8.51   < µ <   9.49   )

orchestra answered 1 year ago

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