Statistics Ques 95% Confidence Interval..

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The data below represents the overall miles per gallon​ (MPG) of 2008 SUVs priced under​ $30,000. Complete parts a and b below.

a. Construct a 95​% confidence interval estimate for the population mean miles per gallon of 2008 SUVs priced under​ $30,000, assuming a normal distribution.

___ ≤ π ≤ ____ (Round to four decimal places as​ needed.)

b. Interpret the interval constructed in​ (a). Choose the correct answer below.

A.With 95​% ​confidence, the mean miles per gallon in the population of 2008 SUVs is somewhere in the interval.

B.With 95​% ​confidence, the mean miles per gallon in the sample of 2008 SUVs is somewhere in the interval.

C.With 95​% ​confidence, the mean miles per gallon in the population of 2008 SUVs is the sample mean.

D.With 95​% ​confidence, the mean miles per gallon in the sample of 2008 SUVs is the population mean.

Answer 1

n = 22, mean = 18.909, standard deviation = 1.9, standard error (SE) = 0.405, z-critical for 95% CI is 1.96

CI = mean +/- z-critical * SE = 18.909 +/- 1.96 * 0.405 = (18.1152,19.7028)

A..With 95​% ​confidence, the mean miles per gallon in the population of 2008 SUVs is somewhere in the interval.