Does it really matter where you grocery shop financially? Are the prices at one grocery store consistently higher or lower than those at another?

“Shopping the grocers,” an article in the December 19, 2004, Democrat & Chronicle, featured a comparison of products bought at four local supermarkets.

The data were analyzed using ANOVA techniques, and the results follow.

One-way ANOVA: Martins, Tops, Wal-Mart, Wegmans Source DF SS MS F P Factor 3 0.50 0.17 0.03 0.993 Error 56 330.74 5.91 Total 59 331.24 S 2.430 R-Sq 0.15% R-Sq(adj) 0.00%

a. State the null and alternative hypotheses.

b. Based on the information on the computer printout shown, state the decision and conclusion to the hypothesis test.

c. Using the statistics given for each store, does there seem to be a difference among the mean grocery cost for these four supermarkets?

d. Using the statistics given for each store, does there appear to be a difference among the standard deviations for these four supermarkets?

e. How do your answers in parts c and d support your answer in part b? Explain.

Transcribed Image Text:

Individual 95% CIs For Mean Based on Pooled StDev Level N Mean StDev Martins 15 2.542 2.241 Tops 15 2.596 2.294 Wal-Mart 15 2.473 2.173 ( Wegmans 15 2.723 2.935 (--- Pooled StDev 2.430 .) --) +-- 1.40 2.10 2.80 3.50