Tests Concerning Means - Mean Numbers of Cameras Sold in 3 Store Chains

A new model of digital camera is marketed in three major department store chains. The number of cameras sold every month at each of three store chains is listed below.

At 0.05 level of significance, is there a difference in the mean numbers of cameras sold at the three department store chains?

SOLUTION:

EXCEL OUTPUT

Since p = 0.0020587 is less than 0.05 level of significance, we can conclude there is a significant difference in the mean number of cameras sold at the three department store chains.

A. State the null and the alternative hypothesis.

ANSWER:
$H_o$: The mean numbers of cameras sold at the three department store chains are all equal.
$H_a$: At least two of the mean numbers of cameras sold at the three department store chains are not equal.

B. Compute SS total, SST, and SSE.

SOLUTION:

C. Develop an ANOVA table

SOLUTION:

D. What is the decision regarding the null hypothesis (is there a difference in the mean numbers of cameras sold at the three department store chains)?

ANSWER:
The decision is to reject the null hypothesis that there is a significant difference in the mean numbers of cameras sold at the three department store chains.

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