Problem Set 1: (22 pts)

A teacher wanted to see if social anxiety affects performance on an oral assignment. To examine this, students completed social anxiety scales and were classified into "low," "average," and "high" levels of social anxiety. The data presented in the table below are the oral presentation grades (in percentages) earned by the 45 students separated by their social anxiety classification. Conduct the most appropriate statistical analysis to determine whether grades on the oral assignment differed based on level of social anxiety. (Hint: see week 1 presentations)

Oral presentation grade (%)

Low Average High

72 80 77

68 85 71

73 73 73

75 81 69

97 73 90

73 91 74

95 73 76

88 73 67

89 71 81

97 75 75

88 78 68

89 90 79

93 89 58

89 88 83

79 75 81

1)What is the dependent variable and its scale of measurement in this scenario? (2 pts)

Grades received by the students in oral assignments is the dependent variable. Scale of measurement is

2)State the independent variable in the scenario, its scale of measurement, and its number of levels. (3 pts)

Social anxiety is the independent variable. Scale of measurement is . There are 3 levels.

3)Paste appropriate SPSS output. (4 pts)

4)Calculate and interpret the effect size. (3 pts)

5)Paste appropriate SPSS graph, formatted in APA (2 pts). What is an appropriate figure caption using APA conventions. 2 pts for graph; 2 pts for caption = 4 pts total.

6)Write in apa style Results section based on your analysis. All homework "Results sections" should follow the examples provided in the presentations and textbooks. They should include the statistical statement within a complete sentence that mentions the type of test conducted, whether the test was significant, and a decision about each null hypothesis tested. Include effect sizes, post hoc analyses / interpretations, and refer the reader to Figure(s) created above, when appropriate (4 pts).

7)Identify a potential confounding variable with the study as it was presented (you can use your imagination!). Justify why you think it may be a confounding rather than an extraneous variable. (2 pts)