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 (three times: 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 researcher recorded the amount of dirt removed. Use a 5% significance level, for all hypothesis tests and confidence intervals. How many treatments were used in this experiment