PSY3901: Experimental Psychology 1
Week 6 Assignment Written Responses
Week 6 Assignment: Co
elation and Regression
Written Response Worksheet
NAME:
Instructions: Follow along with the step-by-step instruction manual provided for the Week 6 assignment. The instruction manual will make specific reference to data interpretation questions that require written responses. Use this worksheet to answer these written response questions. Each question is listed below along with the number of points each question is worth toward the assignment. Type your response in the space provided below each question.
QUESTION 1
3 points
Based on the co
elation coefficient between happiness score at Time 1 and Time 2, does the happiness measure appear to have sufficient test-retest reliability? In your response, report the Pearson r, and explain the criteria you used to make your determination.
QUESTION 2
3 points
Based on the Cronhbach’s alpha statistic, does the four-item happiness measure appear to have sufficient internal consistency (interitem reliability)? In your response, report Cronhbach’s alpha, and explain the criteria you used to make your determination.
QUESTION 3
3 points
As you examine the interitem co
elation matrix and the item-total atatistics (Cronbach’s alpha if in the item deleted column) included in the reliability analysis output, it indicates that one of the four items on the happiness measure is not as strongly co
elated as the other three items. Report which item (1, 2, 3 or 4) the output indicates as being a relatively weaker fit (i.e., not as strongly related with the others) in the measure and what the Cronbach’s alpha would be if this item were to be excluded from the scale.
QUESTION 4
3 points
Based on your intuition, do you expect that there will be a positive relationship, negative relationship, or no relationship between body mass index and self-esteem? Describe the predicted relationship and provide a
ief one-sentence rationale for your prediction.
QUESTION 5
5 points
Paste the scatterplot figure you created showing the relationship between body mass index and self-esteem. Include an APA style title with the figure.
PASTE SCATTERPLOT FIGURE BELOW:
QUESTION 6
3 points
Describe the nature of the relationship between body mass index and self-esteem score based on the scatterplot figure. What is the direction and strength of the relationship?
QUESTION 7
5 points
In about two sentences, report and interpret the results of the Pearson co
elation in APA style. Report the co
elation coefficient in co
ect statistical notation. Also report the coefficient of determination as a measure of effect size. Finally, interpret the findings (i.e., was there evidence for a significant relationship between body mass index and self-esteem? If so, what was the nature of the relationship?)
INCLUDE RESPONSE IN APA FORMAT BELOW:
Results
QUESTION 8
3 points
Interpret and report the co
elations between each of the predictor variables (self-esteem, physical health, and psychological health) and the outcome variable happiness. Describe which variables are related to happiness, how they are related, and the strength of the relationships.
QUESTION 9
5 points
Write a
ief report in APA style summarizing the results of the regression analysis specified in Model 1 that examined if self-esteem was a significant predictor of happiness. Report and interpret the R-square of the model. Also, report the ANOVA table results and the standardized coefficient weight (Beta) for the self-esteem score for Model 1. Finally, provide at least one sentence interpreting the findings (i.e., is self-reported self-esteem a good predictor of self-reported happiness?)
INCLUDE RESPONSE IN APA FORMAT BELOW:
Results
QUESTION 10
2 points
Specify the regression equation [HappyScorei = b0 + bSelfEsteemScore × SelfEsteemScorei] for Model 1 that examined self-esteem as a predictor of happiness.
*Hint: Enter the B-values into the equation above for b0 (B-value for the Model 1 Constant) and bSelfEsteemScore (B-value for SelfEsteeemScore in Model 1).
QUESTION 11
2 points
Using the regression equation for the regression Model 1 you just specified in Question #9 above, what would the predicted happiness score (Predicted-Y) be for someone who has a self-esteem score (X) of 30?
*Hint: Enter 30 in the regression equation for SelfEsteemScorei and solve for HappyScorei
QUESTION 12
3 points
Examining the model summary table for Model 2 in the multiple regression output, did the addition of physical health score and psychological health score as predictors improve the fit of the model (i.e., improve the amount of explained variability in happiness scores)? In your answer, report and interpret the R-square change for Model 2 and report the F change results.
QUESTION 13
3 points
Examining the coefficients table for Model 2 in the multiple regression output, which variables were found to be significant predictors of self-reported happiness? In your answer, report and interpret the standardized coefficient weights (Beta) and the t-statistics associated with each predictor in the Model 2 regression analysis.
QUESTION 14
2 points
Overall, based on the measures in the multiple regression analysis, does self-esteem, physical health, or psychological health appear to be the most influential predictor of happiness? Provide evidence from the output supporting your answer.
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PSY3901: Experimental Psychology 1
Week 6 Assignment: Co
elation and Regression in SPSS
1
Week 6 Assignment: Co
elation and Regression in SPSS
Step-by-Step Instruction Manual
Week 6 Assignment Overview
For this week’s assignment, you will use a modified version of the health and self-esteem dataset that
we have used on previous assignments. You will be given research tasks that require the use of
co
elational and regression techniques in SPSS to examine relationships between variables included
in the dataset. Along the way you will be asked to interpret and report the results by following the
questions on your Week 6 assignment written response worksheet.
The Week 6 SPSS assignment is worth a total of 60 points. To complete the assignment, you will need
to upload and submit the following two files for grading:
o SPSS Output (.spv) file; this file includes a log of all commands and outputs requested during your
SPSS session for this assignment
o Week 6 Assignment Written Response Worksheet (MS Word file); this file includes your written
esponses to data interpretation questions
Assignment Materials
Download, update, save, and submit the files listed below for this assignment:
o PSY3901 Week 6 Assignment Dataset (Health and Self-Esteem) (SPSS .sav file)
o PSY3901 Week 6 Assignment Written Response Worksheet (MS Word File)
Step-by-Step Instructions
1: Open the Dataset and Create a New Output File for the Assignment
1. Open the Week 6 assignment dataset.
2. Open a new SPSS output file to keep track of all your SPSS activity during the assignment.
3. Add a header to your output file that reads: PSY3901 Week 6 SPSS Assignment – YOUR NAME.
4. Save the output file. Be sure to log all assignment SPSS activity in this output file, and save it
egularly. You will be submitting this output file as part of your assignment.
2: Examining the Test-Retest Reliability of Happiness Score Measure (2 points for output)
As you survey the health and self-esteem dataset for Week 6, you will notice one new variable included
within the dataset with the name HappyScore2. In order to obtain the HappyScore2 measure, we had
the same participants come back five weeks later to fill out the same four-item happiness measure. We
then computed their overall happiness score on this measure again. The purpose of having the same
participants fill out the same measure a second time was to evaluate the test-retest reliability of the
happiness measure. If a measure is consistent over time (i.e., has test-retest reliability), then
participants should obtain very similar scores on the measure each time it is administered. We can use
PSY3901: Experimental Psychology 1
Week 6 Assignment: Co
elation and Regression in SPSS
2
a Bivariate Co
elation in SPSS to test if the happiness measure has strong test-retest reliability. In
SPSS, run a co
elation between HappyScore and HappyScore2 to examine if the measure has
sufficient test-retest reliability. In this case, we are not interested in if the co
elation is significant, but
ather the overall strength of the co
elation coefficient. Specifically, the co
elation should be +.70 or
above for us to feel confident about the test-retest reliability of the happiness measure used in our
survey.
1. Go to Analyze Co
elate Bivariate…
2. Add the HappyScore and HappyScore2 from the variable list to the Variables: box. Under
Co
elation Coefficients make sure that Pearson is checked, and under Test of Significance make
sure Two-tailed is selected. Under Options… you can choose Means and standard deviations and
Cross-product deviations and covariances if you like.
3. Click OK to run the co
elation.
4. Use the Pearson co
elation output to answer Question #1 on your Assignment 6 written response
worksheet.
QUESTION 1 3 points
Based on the co
elation coefficient between happiness score at time 1 and time 2, does the
happiness measure appear to have sufficient test-retest reliability? In your response, report
the Pearson r, and explain the criteria you used to make your determination.
3: Internal Consistency (Inter-Item Reliability) of the Happiness Measure (3 points for output)
Another type of the reliability that is of interest for the happiness measure is internal consistency or
inter-item reliability. In this case, what we are interested in is if all four items included on the happiness
measure are consistent with one another (i.e., are all measuring the same variable or construct). To
examine if the four-item happiness measure has sufficient internal consistency, use Reliability
analysis in SPSS to generate Cronbach’s alpha, inter-item co
elations, and “Scale if item deleted”
descriptives. An overall Cronhbach’s α of .70 or above usually provides sufficient evidence for high
internal consistency across items on a measure.
1. Go to Analyze Scale Reliability Analysis…
2. Add the four happiness measure items (Happy1, Happy2, Happy3, and Happy 4_Reverse) from
the variable list to the Items: box. Under Model, make sure that Alpha is selected from the drop-
down menu options.
3. Click the Statistics… button and, under Descriptives for, check to include Scale if item deleted.
Also, under Inter-Item, check the Co
elations box. Then click Continue.
4. Click OK to run the co
elation.
5. Use the Reliability Analysis output to answer the questions shown below on your Assignment 6
written response worksheet.
PSY3901: Experimental Psychology 1
Week 6 Assignment: Co
elation and Regression in SPSS
3
QUESTION 2 3 points
Based on the Cronhbach’s Alpha statistic, does