A psychologist is examining the educational advantages of a preschool program and suspects that there will be significant differences in achievement based on preschool attendance. Twenty-four randomly selected 4th grade children are used in the study. Half attend a preschool program and half do not. Each child's achievement score is given below. Make sure to use the appropriate t-test for this analysis!
Preschool: 8, 6, 8, 9, 7, 9, 6, 9, 8, 9, 7, 8
No Preschool: 6, 5, 7, 6, 8, 5, 7, 5, 6, 7, 5, 6
What is the null and alternative hypothesis (in symbols) for this t-test?