Popcorn again. Refer to the experiment in Exercise 1. After collecting her data and analyzing the results, the student reports that the F-ratio for Power is 13.56 and the F-ratio for Time is 9.36.
a) What are the P-values?
b) What would you conclude?
c) What else about the data would you like to see in order to check the assumptions and conditions?
Exercise 1
Popcorn revisited. A student runs a two-factor experiment to test how microwave power and temperature affect popping. She chooses 3 levels of Power (low, medium, and high) and 3 Times (3 minutes, 4 minutes, and 5 minutes), running one bag at each condition. She counts the number of uncooked kernels as the response variable.
a) What are the null and alternative hypotheses for the main effects?
b) How many degrees of freedom does each factor sum of squares have? How about the error sum of squares?
c) Should she consider fitting an interaction term to the model? Why or why not?