Four different paints are advertised to have the same drying times. Use the Kruskal Wallis Test – Analysis of Variance by Ranks, to verify the manufacturer’s claim. Remember that seven samples were tested for each of the paints. The time in minutes until the paint was dry enough for a second coat to be applied was recorded. Below are the results. Paint 1 Rank Paint 2 Rank Paint 3 Rank Paint 4 Rank
114 112 126 115 117 118 127 117 120 118 128 122 121 118 129 123 126 120 131 123 126 121 131 126 130 121 137 126
H0: the population distributions of drying times are the same for the four samples H1: the population distributions of drying times are not all the same for the four samples
a. State your test statistic:
b. State your decision rule: (α = 0.05)
c. Show your calculation:
d. What is your conclusion?