An experiment evaluating the effectiveness of an intervention for improving attitudes about something finds that the mean posttest score of the experimental group is 70, which is better than the control group’s mean posttest score of 65. The significance level is .05, and the p value is .01. The standard deviation is 5.
-The Cohen's d effect size statistic is +1.0.

Question

An experiment evaluating the effectiveness of an intervention for improving attitudes about something finds that the mean posttest score of the experimental group is 70, which is better than the control group’s mean posttest score of 65. The significance level is .05, and the p value is .01. The standard deviation is 5. 
-The Cohen's d effect size statistic is +1.0.

Quizplus · Accepted Answer

The statement is true. The Cohen's d effect size statistic is +1.0 indicates a large effect size, which means the intervention had a significant impact on improving attitudes about something. The p value of .01 is less than the significance level of .05, which also indicates that the results are statistically significant. The mean posttest score of the experimental group (70) is higher than the control group's mean posttest score (65), which further supports the effectiveness of the intervention.

An Experiment Evaluating the Effectiveness of an Intervention for Improving