Students in a business statistics course performed a completely randomized desig
ID: 3049669 • Letter: S
Question
Students in a business statistics course performed a completely randomized design to test the strength of four brands of trash bags. One-pound weights were placed into a bag, one at a time, until the bag broke. A total of 24 bags, 6 for each brand, were used. The data in the accompanying table give the weight (in pounds) required to break the trash bags. At the 0.05 level of significance, is there evidence of a difference in the variation in strength among the four brands of trash bags?
Brand 1 Brand 2 Brand 3 Brand 4
30 41 33 23
38 35 33 18
32 36 39 20
42 41 35 20
37 32 34 20
34 38 34 17
Explanation / Answer
p-value = 0.0000 < 0.05
hence
we reject the null hypothesis
At the 0.05 level of significance, there is significant evidence of a difference in the variation in strength among the four brands of trash bags
Anova: Single Factor SUMMARY Groups Count Sum Average Variance brand 1 6 213 35.5 19.1 2 6 223 37.16666667 12.56666667 3 6 208 34.66666667 5.066666667 4 6 118 19.66666667 4.266666667 ANOVA Source of Variation SS df MS F P-value F crit Between Groups 1187.5 3 395.8333333 38.61788618 1.64662E-08 3.098391212 Within Groups 205 20 10.25 Total 1392.5 23