SOLUTION: Test the claim that the mean lifetime of car engines of a particular type is greater than 22,000 miles. sample data are summarized as n=23, x bar = 226,450 miles, and s=11,500 mile

Question 1057595: Test the claim that the mean lifetime of car engines of a particular type is greater than 22,000 miles. sample data are summarized as n=23, x bar = 226,450 miles, and s=11,500 miles. us a significance level of alpha=0.01
Answer by Boreal(15235) (Show Source): You can put this solution on YOUR website!
Ho:lifetime is 220,000 miles. I think 22,000 miles was a typographical error.
Ha: it isn't
alpha=0.01
test statistic is a t (0.995, df=22)
critical value, |t|>2.819
equation (xbar-mean)/s/sqrt (23)
t=(220,000-226,450)/11500/sqrt (23)
=-6450*sqrt(23)/11500=-2.69
The null hypothesis is not rejected at the 0.01 level. The mean lifetime may be 220,000 miles

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