Reference no: EM132465135

Problem: A clinic specializing in eating disorders would like to evaluate the effectiveness of a nutritional training program on binge eating disorder (BED). A psychologist was hired to conduct a small study to examine the potential effect of nutritional training on number of binges per month. The psychologist recruited 10 patients in the clinic to participate in a nutritional training program and 12 patients in the clinic with similar demographics who do not participate in the nutritional program. Afterward, all participants reported the number of binges from the previous month. The data are listed in the table below. The psychologist is not predicting a particular direction of the potential differences between the two groups and she sets the alpha level at .05 for the hypothesis test.

Nutritional training

Subject ID # # of binges    

1 6

2 4

3 2

4 5

5 3

6 5

7 5

8 3

9 7

10 3

 

No nutritional Training

Subject ID # # of binges

11 7

12 8

13 6

14 4

15 7

16 6

17 3

18 8

19 9

20 6

21 7

22 5

1. What is the dependent (outcome) variable? What is the independent (grouping) variable?
2. Create the null and alternative hypotheses for this study, using both words and symbol notation
3. Calculate M₁ andM₂
4. Calculate df₁ , df₂, and df_total
5. Calculate ^s2₁ and s²₂ (estimated variance for population 1 and variance for population 2)
6. Calculate the pooled variance for the two populations
7. Use the pooled variance to calculate the variance for sampling distribution 1 and the variance for sampling distribution 2
8. Calculate standard deviation of the comparison distribution
9. Calculate the t statistic
10. Considering the research question and the hypotheses, should the test be one-tailed or two-tailed? Why?
11. Determine the critical t value(s) for this hypothesis test based on the degree of freedom, from (d), and the preset alpha level.
12. Compare the calculated t statistic with the critical t value by stating which is more "extreme", and then make a decision about the hypothesis test by stating clearly "reject" or "fail to reject" the null hypothesis.
13. Calculate the pooled standard deviation for the populations and then use it to calculate the standardized effect size of this test.