Describe completely randomized design experiments. Select the FALSE statement about completely random design. a.)The additional variables affect different control groups differently. b.)Subjects are randomly assigned to treatments. c.)It minimizes the effects of confounding variables. d.)Any number of treatments may be addressed.

Exercise is known to produce positive psychological effects. Interestingly, not all exercise is equally effective. It turns out that exercising in a natural environment (e.g., jogging in the woods) produces better psychological outcomes than exercising in urban environments or in homes (Mackay & Neill, 2010). Suppose that a sports psychologist is interested in testing whether there is a difference between exercise in nature and exercise in the lab with respect to post-exercise anxiety levels. The researcher recruits n 5 7 participants who exercise in the lab and exercise on a nature trail. The data below represent the anxiety scores that were measured after each exercise session.   Treat the data as if the scores are from an independent-measures study using two separate samples, each with n 5 7 participants. Compute the pooled variance, the estimated standard error for the mean difference, and the independent-measures t statistic. Using a 5 .05, is there a significant difference…

Researchers investigate how the presence of cell phones influence the quality of human interaction.  Subjects are randomly selected from a population and divided into an experimental group that is asked to leave their phones in the front of the room and a control group that are not asked to leave their cell phones at the front of the room.  Subjects are left alone for 10 minutes and then asked to take a survey designed to measure quality of interactions they had with others in the experiment.  What statistical test is appropriate?

A school psychologist is interested in whether a particular remedial math training program helps improve students’ math skills. He randomly assigns 18 students to one of two groups: remedial training or no intervention. At the end of the training program, he administers a 100 point math test to all students, and counts the number of errors made by students in each group. These data (number of errors per student) are shown below.   NO INTERVENTION                 REMEDIAL TRAINING 18                                                                      12          6 17                                                                      8 13                                                                      13 15                                                                      12 19                                                                      6 22                                                                      10 19…