Tracy works in a drugstore photodeveloping department Over t

Tracy works in a drugstore photo-developing department. Over time, Tracy felt that the number of rolls of film brought in for development varied among the days of the week. Were the weekends having an effect one way or another? Tracy decided to keep a daily record of the number of rolls of film dropped off for development for 4 weeks. Her results are in the following table.

Using a one-way ANOVA, test the claim that the mean number of rolls of film dropped off is not the same for all 7 days of the week. Use a level of significance of .05.

(a) Find the test statistic. (Give your answer correct to two decimal places.)


(b) Find the critical value. (Give your answer correct to two decimal places.)

(c) State the appropriate conclusion.
Reject the null hypothesis, there is not significant evidence of a difference in mean number of rolls of film?

Reject the null hypothesis, there is significant evidence of a difference in mean number of rolls of film?

Fail to reject the null hypothesis, there is significant evidence of a difference in mean number of rolls of film?

Fail to reject the null hypothesis, there is not significant evidence of a difference in mean number of rolls of film?

Solution

Using the Data Analysis function in Excel, running an ANOVA: Single Factor, we see that

F = 3.443843519 [ANSWER, PART A]

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We also see in the table that

Fcrit = 2.572711641 [ANSWER, PART B]

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As we see, F > Fcrit (also, p = 0.0158 < 0.05), then we REJECT THE NULL HYPOTHESIS.

Thus, it is option B: REJECT THE NULL HYPOTHESIS, THERE IS significant evidence of a difference in mean number of rolls of film [ANSWER, OPTION B]