A well-known conglomerate claims that its detergent "whitens and brightens better than all the rest." In order to compare the cleansing action of the top three detergents, 15 swatches of white cloth were soiled with red wine and grass stains and then washed in front-loading machines with the respective detergents. The following whiteness readings are shown in the accompanying table. The data are also on the text website, labeled Detergents
a. Specify the competing hypotheses in order to test whether differences exist in the cleansing action of the three detergents.
b. Calculate the value of the test statistic H.
c. Approximate the p-value.
d. At the 1% significance level, does cleansing action differ by detergent? Explain.