# We Compared the Weight Reduction of the Therapy and Control Groups Using an Independent

Psyc 3214 Final (48 pts)

Type your answers below, preferably in another font.Use the hand-outs I gave you in class to help determine which test to run. Print and turn in all of the requested output to Ashley’s mailbox with your answers below.Do not send e-mail responses.

Imagine a study conducted to test the effectiveness of a weight-loss therapy. The researchers randomly assign 30 people to two,independent groups: therapy and control (15 people per group). At the conclusion of the therapeutic intervention, they measure the amount of weight gain or loss in pounds. The results are recorded so that a positive value indicates a loss in weight (a “positive” outcome), and a negative number indicates weight gain. The data follow:

Control: -3, 1, 3, -1, 1, -5, 3, -3, -4, -3, 1, -7, -2, 2, 3
Therapy: 7, 4, 4, 6, 5, -3, -1, -2, -1, -1, -2, 6, 8, -1, -2

Enter the data into SPSS and obtain descriptive statistics. Also, run the appropriate t-test. Print your SPSS results (14pts), and using a word processorreplace the ‘xx’ values in the text below (8pts) with the values obtained from SPSS (report two-decimal precision where possible). You will have to compute Cohen’s d by hand.

We compared the weight reduction of the therapyand controlgroups using at-test. The results were statistically significant, t(xx) = xx, p = .xx, and indicated that the individuals in the therapy group (M = xx lbs., SD = xx) lost more weight than the individuals in the control group (M = xx lbs., SD = xx). The observed effect size was also large according to Cohen’s conventions, d = xx. The 95% confidence interval, however, indicated only moderate precision in the estimated difference between the two population means (xx to xx lbs.in weight reduction).

Based on these results, the therapy was (effective / not effective ) (highlight/boldenthe answer, 2pts)

Consider two variables : handedness and eye color. Are these two nominal (categorical) variables associated in the population? Create numerical codes for the data below (e.g., 1 = left, 2 = right; 1 = blue, 2 = brown, etc.), and enter the numbers into SPSS, being sure to then label your values. Run the appropriate statistical test to see if the variables are associated. Print your SPSS output (14pts) and write a brief summary of the results (7 pts), being sure to include an index of effect size (computed by hand 3pts) in your summary.

Dom Hand Eye Color

LeftBlue

RightBrown

RightBrown

RightBrown

LeftBrown

LeftBlue

RightBrown

RightGreen

RightBlue

RightGreen

RightBrown

LeftBlue

LeftBlue

RightBrown

RightBrown

LeftGrey

RightBlue

RightBrown

RightBrown

RightBrown

LeftBlue

LeftBrown

RightGrey

RightBrown

LeftBlue