Suppose a developmental psychologist wants to reduce the achievement gap between low-income and middle-income children. He thinks that middle-income children go to kindergarten already knowing more that low-income children because middle income children get more educational opportunities before kindergarten. He provides free preschool to a group of low-income students to increase their achievement scores. The achievement test scores of those students in 5th grade are assessed, and compared to the average score of previous low-income 5th graders of 61 on the test. The Answer the following questions with = .10.

Participant	Achievement Score in 5thGrade
1	67
2	73
3	70
4	62
Average	68

What is your null hypothesis (H₀)?

What is your research hypothesis (H₁)?

Calculate the appropriate statistic.

Estimate and interpret the effect size