# Question: A study was designed to measure the effect of home

A study was designed to measure the effect of home environment on academic achievement of 12-year-old students. Because genetic differences may also contribute to academic achievement, the researcher wanted to control for this factor. Thirty sets of identical twins were identified who had been adopted prior to their first birthday, with one twin placed in a home in which academics were emphasized (Academic) and the other twin placed in a home in which academics were not emphasized (Nonacademic). The final grades (based on 100 points) for the 60 students are given here.

a. Is there a difference in the mean final grades between the students in an academically oriented home environment and those in a nonacademically oriented home environment. Use α = .05.

b. Estimate the size of the difference in the mean final grades of the students in academic and nonacademic home environments using a 95% confidence interval.

c. Do the conditions for using the t procedures appear to be satisfied for these data?

d. Does it appear that using twins in this study to control for variation in final scores was effective as compared to taking a random sample of 30 students in both types of home environments? Justify your answer.

a. Is there a difference in the mean final grades between the students in an academically oriented home environment and those in a nonacademically oriented home environment. Use α = .05.

b. Estimate the size of the difference in the mean final grades of the students in academic and nonacademic home environments using a 95% confidence interval.

c. Do the conditions for using the t procedures appear to be satisfied for these data?

d. Does it appear that using twins in this study to control for variation in final scores was effective as compared to taking a random sample of 30 students in both types of home environments? Justify your answer.

## Answer to relevant Questions

Conduct a test of H0: μ1 ≥ μ2 –2.3 versus Ha: μ1 < μ2 – 2.3 for the sample data summarized here. Use α = .01 in reaching your conclusions. Use the level and power values for the paired t test and Wilcoxon signed-rank test given in Table 6.18 to answer the following questions: a. Suppose a level .05 test is to be applied to a paired data set that has ...An environmental impact study was performed in a small state to determine the effectiveness of scrubbers on the amount of pollution coming from the cooling towers of a chemical plant. The amounts of pollution (in ppm) ...In an effort to link cold environments with hypertension in humans, a preliminary experiment was conducted to investigate the effect of cold on hypertension in rats. Two random samples of 6 rats each were exposed to ...Based on the land office’s decision in the test of hypotheses, could it have made (select one of the following) a. A Type I error? b. A Type II error? c. Both a Type I and a Type II error? d. Neither a Type I nor a ...Post your question