A manufacturer of household washing machines wants to determine the effectiveness of the type of detergent used (three brands –
A, B, and C) and the length of time for the washing cycle (18, 20, and 22 minutes). The manufacturer prepared 18 standard household laundry loads (having equal amounts of dirt and the same total weight) to conduct the study. The manufacturer randomly assigned two loads to each type of detergent, time combination. The researcher recorded the amount of dirt removed. Use a 5% significance level, for all hypothesis tests and confidence intervals. What is the alternative hypothesis for testing the interaction?
Length of time for the washing cycle : A = 18 mins, B = 20 mins, C = 22 mins
number of laundry loads = 18
significance level = 5%
The alternative hypothesis for testing the interaction is a Two-Factor ANOVA with replication this is because the factors that have variations are the : The type of detergent and the length of time for a washing cycle while the load is constant for all.
