A psychologist examines retention of a learned task in monkeys. At 90 days 5 monkeys are trained on a discrimination task. Then their performance is tested again at 4 months, 6 months, and 1 year. A partial ANOVA summary table follows. The data were analyzed using a repeated-measures ANOVA. Answer the following: Describe the null and alternative hypotheses. Then complete the source table. Source SS df MS F Between treatments 1 1 Within treatments Between subjects Error 40 Total 143