Your population mean has always been 9 customers per hour Th

Your population mean has always been 9 customers per hour. The sample standard deviation is 4. The sample size is 25. The sample mean is 8. .05 is your level of significance. Use your sample data to test the claim that the number of customers you are serving per hour has changed. Choose the most accurate answer to running this hypothesis test.

Solution

Let mu be the population mean

The test hypothesis:

Ho: mu=9 (i.e. null hypothesis)

Ha: mu not equal to 9 (i.e. alternative hypothesis)

The test statistic is

t=(xbar-mu)/(s/vn)

=(8-9)/(4/sqrt(25))

=-1.25

It is a two-tailed test.

The degree of freedom =n-1=25-1=24

Given a=0.05, the critical values are t(0.025, df=24) =-2.06 or 2.06 (from student t table)

The rejection regions are if t<-2.06 or t>2.06, we reject the null hypothesis.

Since t=-1.25 is between -2.06 and 2.06 , we do not reject the null hypothesis.

So we can not conclude that the number of customers you are serving per hour has changed.

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Answer:E. None of the above