Solved: A study was made to determine if humidity

Chapter 14, Problem 14.35

(choose chapter or problem)

A study was made to determine if humidity conditions have an eect on the force required to pull apart pieces of glued plastic. Three types of plastic were tested using 4 dierent levels of humidity. Theresults, in kilograms, are as follows: Humidity Plastic Type 30% 50% 70% 90% A 39.0 33.1 33.8 33.0 42.8 37.8 30.7 32.9 B 36.9 27.2 29.7 28.5 41.0 26.8 29.1 27.9 C 27.4 29.2 26.7 30.9 30.3 29.9 32.0 31.5 (a) Assuming a xed eects experiment, perform an analysis of variance and test the hypothesis of no interaction between humidity and plastic type at the 0.05 level of signicance. (b) Using only plastics A and B and the value of s2 from part (a), once again test for the presence of interaction at the 0.05 level of signicance.