Assignment 4

TPSYCH 309: Assignment 4

t-tests

1.

Laio (2007) reported the results of a comparison of two different weight-loss programs. In the study, obese participants were randomly assigned to one of two groups: (1) the soy group, a low-calorie group that ate only soy-based proteins, or (2) the traditional group, a low-calorie group, in which participants received 2/3 of their protein from animal products and 1/3 from plant products. One of the dependent measures collected was the amount of body fat loss as a percentage of initial body weight. Fictional data on the percent of body fat loss follows.   Soy Diet Traditional Diet 2.50 2.11 1.70 0.86 2.31 1.28 1.90 1.23 2.0 0.50 3.2 1.76 2.4 2.00 1.3 1.30 2.9 .50 2.25 .76 1.95 1.01 3.34 .45 2.84 .38 1.98 .59 2.04 1.24 4.01 .92

 

Questions:

1. a) What statistical analysis would you run and why?
2. b) How would you do this in SPSS? Give the step by step process.

 

 

 

 

 

 

 

 

 

 

 

 

2. Fifteen people participate in a coordination study. They are each timed for how long they can jump rope without a mistake with their eyes open. Then, they each repeat the task with their eyes closed. For each individual, the difference in times is calculated. The purpose of the study is to determine if the lack of vision in normally seeing individuals decreases coordination. Data are represented below:

Eyes open	Eyes closed
15	12
30	16
38	7
67	20
40	37
20	12
45	13
40	16
35	21
60	19
50	14
52	8
35	11
57	12
44	22

 

Questions:

1. a) What statistical analysis would you run and why?
2. b) How would you do this in SPSS? Give the step by step process.

 

 

3. Read the following:

Carcoran, K. Hundhammer, T., & Mussweiler, T. (2009). A tool for thought! When comparative thinking reduces stereotyping effects. Journal of Experimental Social Psychology, 45, 1008-1011. http://dx.doi.org/10.1016/j.jesp.2009.04.015

 

Now answer the following questions in relation to this article.

 

 

1. a) What was the overall goal and hypotheses of this research?

 

 

STUDY 1:

1. b) Summarize the methods.
2. c) What did they find? Did their findings support their hypothesis?
3. d) What type of t-test was used and why? (In other words, why was this the appropriate analysis?)
4. e) In class we focused on two main types of t-tests. Given your answer for d) why was the other type of t-test not appropriate? How could you have changed the design of the study to make this t-test appropriate? Would it make sense to do this (why or why not)?

 

STUDY 2:

1. f) Summarize the methods.
2. g) What did they find? Summarize the results. Did their findings support their hypothesis?
3. h) Note that researchers used an ANOVA. Why do you think they used and ANOVA and not just a t-test here?
4. i) Researchers also used t-tests here. For what variables did they use a t-test for and why?