Data Analysis 1

Instructions and Guidelines

Overview/Goal: to review and perform analyses involving 2 treatment conditions (one factor - 2 levels), utilizing graphical, numerical and descriptive summaries from two experiments.

Details: you should submit a brief report with figures answering the questions posed here.

1.         A clinical psychologist is comparing two methods of reducing anxiety. From among those attending an anxiety clinic, he randomly selects 8 people for Method A and 8 people for Method B. Following therapy, each of the 16 participants gives a speech in front of the others and they are scored on a scale of 1 (least anxious) to 16 (most anxious). Are there differences in the effects of the two methods? Use a = .05 to conduct your hypothesis test. Present a graph of the data, summarizing the results of the study. Be sure to include both measures of central tendency and variability in your graphs. Write a statement about your findings, using your book as a guide.

(From Glenberg and Andrzejewski (2007) Learning from Data, 3rd Ed.)

2.        To ensure that she didn’t compromise her experiment with non-equivalent groups, the clinical psychologist repeated her experiment within-subject. She recruited 12 participants from an anxiety clinic for her new study. Half the participants received Method A first, half received Method B. They were then tested in an equivalent fashion as noted above. Then the group that received Method A, received Method B and tested again. The opposite happened for the other half (Method B then Method A). Scores are presented below. Are there differences in the effects of the two methods? Use a = .05 to conduct your hypothesis test. Present a graph of the data, summarizing the results of the study. Be sure to include both measures of central tendency and variability in your graphs. Write a statement about your findings, using your book as a guide. Why did the clinical psychologists obtain different results? Was there any fault in her logic?