An educator believes that new reading activities in the classroom will help elementary school pupils improve their reading ability. She recruits 44 third-grade students and randomly assigns them into two groups. One group of 21 students does these new activities for an 8 week period. A control group of 23 third-graders follows the same curriculum without the activities. At the end of the 8 weeks, all students are given the Degree of Reading Power (DRP) test, which measures the aspects of reading ability that the treatment is designed to improve. Here are parallel boxplots of the data:

a. Write a few sentences comparing the DRP scores for the two groups.

After checking that the conditions for inference are met, the educator performs a test of H₀: versus H_a: , where = the true mean DRP score of third-graders like these who do the new readingactivities and μC = the true mean DRP score of third-graders like these who follow the same curriculum without the activities. Computer output from the test is shown.

b. What conclusion should the educator make at the  significance level?

c. Can we conclude that the new reading activities caused an increase in the mean DRP score? Explain your answer.

d. Based on your conclusion in part (b), which type of error—a Type I error or a Type II error—could you have made? Explain your answer.

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10 20 30 40 50 60 70 80 DRP score Group Control Activities