The data in the table represent the number of corn plants in randomly sampled rows (a 17-foot by 5-inch strip) for various types of plot. An agricultural researcher wants to know whether the mean number of plants for each plot type are equal.

(a) Write the null and alternative hypotheses.
(b) State the requirements that must be satisfied to use the one-way ANOVA procedure.
(c) Use the following partial Minitab output to test the hypothesis of equal means at the a = 0.05 level of significance.

(d) Shown are side-by-side boxplots of each type of plot. Do these boxplots support the results obtained in part (c)?

(e) Verify that the F-test statistic is 7.10.
(f) Verify the residuals are normally distributed.

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Plot Type Sludge plot Spring disc Number of Plants 30 25 27 33 28 27 34 32 33 30 35 34 No till 26 25 30 32 29 29 One-way ANOVA: Sludge Plot, Spring Disc, No Till Source Factor Error Total df 2 MS 42.06 5.92 7.10 0.007 84.11 15 17 88.83 172.94