Week 5 Independent t Test Exercises
Part I
The hypothesis being tested is: Women who are working will have a lower level of depression as compared to women who are not working.
Using Polit2SetC SPSS dataset, which contains a number of mental health variables, determine if the above hypothesis is true.
Follow these steps when using SPSS:
1. Open Polit2SetC dataset.
2. Click Analyze then click Compare Means, then Independent Sample T-test.
3. Move the Dependent Variable (CES_D Score "cesd") in the area labelled Test Variable.
4. Move the Independent Variable (Currently Employed "worknow") into the area labelled Grouping Variable. The worknow variable is coded as (0= those women who do not work and 1= those women who are working). Click on Define Groups in group 1 box type 0 and in group 2 box type 1. Click Continue.
5. Click continue and then click OK.
Assignment: Through analysis of the data and use of the questions below write one to two paragraphs summarizing your findings from this t-test.
1. How many women were employed versus not employed in the sample?
2. What is the total sample size?
3. What are the mean (SD) CES-D scores for each group?
4. Interpret the Levene's statistic. (Hint: Is the assumption of homogeneity of variance met? Are equal variances assumed or not assumed?)
5. What is the value of the t-statistic, number of degrees of freedom and the p-value?
6. Does the data support the hypothesis? Why or why not?
Part II
Hypothesis: Women who reported depression scores in wave 1 and wave 2 of the study did not have a significant difference in their level of depression.
Using Polit2SetC SPSS dataset, determine if the above hypothesis is true.
Follow these steps when using SPSS:
1. Open Polit2SetC dataset.
2. Click Analyze then click Compare Means, then Paired Samples T-test.
3. First click on CES-D Score (cesd) and move it into the box labelled Paired Variables (in the rectangle for Pair 1 of Variable 1 and then click on CESD Score, Wave 1 (cesdwav1) and move it into the Paired Variables box (in the rectangle next to CES-D Score, pair 1, variable 2).
4. Click continue and then click OK.
Assignment: Through analysis of the data and use of the questions below write one to two paragraphs summarizing your findings from this t-test.
1. What is the total sample size?
2. What are the mean (SD) CES-D scores at wave 1 and wave 2?
3. What is the mean difference between the two time periods?
4. What is the value of the t-statistic, number of degrees of freedom and the p-value(sig)?
5. Does the data support the hypothesis? Why or why not?
Part III
Using Polit2SetC dataset, run independent groups t-tests for three outcomes. The outcome variables are CES-D Score (cesd), SF12: Physical Health Component Score, standardized (sf12phys) and SF12: Mental Health Component Score, standardized (sf12ment).
Follow these steps when using SPSS:
1. Open Polit2SetC dataset.
2. Click Analyze then click Compare Means, then Independent Sample T-test.
3. Move the Dependent Variables (CES_D Score "cesd", SF12: Physical Health Component Score, standardized (sf12phys), and SF12: Mental Health Component Score, standardized (sf12ment) ) in the area labelled Test Variable.
4. Move the Independent Variable (Educational Attainment "educatn") into the area labelled Grouping Variable. The educatn variable is coded as (1= no high school credential and 2=diploma or GED). Click on Define Groups in group 1 box type 1 and in group 2 box type 2. Click Continue.
5. Click continue and then click OK.
Assignment: Create a table to present your results, use the table 6.3 in Chapter 6 as a model. Write one or two paragraphs explaining your results.