Exam 9: Experimental Design and Analysis I

A college student is interested in whether there is a difference between male and female students in the amount of time spent working out each week. The student gathers information from a random sample of male and female students on her campus. Amount of time spent working out is normally distributed. The data appear below.​ a) What statistical test should be used to analyze these data? b) Identify H₀ and H_a for this study. c) Conduct the appropriate analysis. d) Should H₀ be rejected? What should the researcher conclude? e) If significant, compute the effect size and interpret this. f) If significant, draw a graph representing the data.

A health magazine recently reported a study in which researchers claimed that iron supplements increased memory and problem-solving abilities in a random sample of college women. All of the women took memory and problem-solving tests at the beginning of the study, then took iron supplements, and then took the same tests again at the end of the study. What is wrong with this design? What confounds could be leading to the results of improved memory and problem-solving skills?​

Increasing the number of levels of the independent variable is to _____ replication as changing the type of dependent measure is to _____ replication.​

After participating in an experiment on the effects of alcohol on sociability, Megan could not wait to return to her sorority house to tell all of her sisters about it. In this situation, the researcher should be concerned with the confound of​

For an independent-groups t test, effect size can be measured using​

After grading 20 very poor term papers, Professor Jones was so upset by his students' writing that he became even more conscious of errors in their papers. Professor Jones' change in his grading criteria is similar to the confound of

The alternative hypothesis for a two-tailed independent-groups t test states that​

Briefly explain the confounds of history and maturation.​