Homework 2
Use the Dataset associated with this assignment in Moodle
Directions: Respond to the prompts below. Follow the ‘Do Not’ and ‘Do’ instructions.
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DO NOT :
· Upload your Excel workbook to Moodle · Copy and paste the dataset values into this document · Upload your work as a Word document in Moodle · Report data values in your submission (residuals etc …)
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DO
· Paste or type your responses directly into this document · Save your completed work as a PDF file · Upload your only your PDF file to Moodle · Format ALL tables and charts using APA formatting · Use APA in-text referencing when writing interpretations and referencing tables and charts
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- Using the Descriptive Statistics feature , of JASP, generate ONE numerical summary table for all interval level or above variables in the dataset. Copy and paste the ONE table into this document. Ensure that the table is APA formatted correctly.
- Using complete sentences, write a STATISTICAL rationale justifying whether the mean or the median is likely the most representative measure of center. PICK ONLY ONE OF THEM. Base your reasoning on the numerical summaries generated in JASP in #1 above. You should report what the representative measure of center (mean or median) for EACH INTERVAL LEVEL OR ABOVE VARIABLE that is in the dataset.
Only after you have determined the measure of center (either mean or median), select the appropriate measure of spread FOR EACH INTERVAL LEVEL OR ABOVE VARIABLE (standard deviation or IQR) to associate with your measure of center choice. Type your responses in the table below (APA format … expand the rows as needed)
Table 1
Measures of center and variability
| Variable | Measure of the Center | Measure of Spread | Justification for measure of center choice |
- Use the Correlation feature, of the Data Analysis ToolPak in Excel, to generate ONE correlation table for all interval level or above variables in the dataset. Using complete sentences, write a STATISTICAL interpretation (report strength and direction) AND an APPLIED interpretation of each UNIQUEcorrelation value listed in the table.
- Choose 2 continuous variables (your choice). Use Excel to generate a scatter plot for two of the continuous variables. Copy and Paste the scatterplot here. Ensure that the chart is APA formatted.
- Describe what the dot pattern, in the scatter plot from #3 above, reveals about the type of relation between the two variables (linear or non-linear)
- Does the scatterplot dot pattern you describedin #4match what you obtained for your correlation value, between the 2 variables, in #2 above?
- Using the Regression feature, of JASP, generate the 3 Simple Regression output tables using one of your selected continuous variables from #3 as the explanatory variable and the other as the response variable. Copy and paste all 3 tables here.
- Using complete sentences, interpret the Multiple R and R Squaredvalues in the Model Summary table. What do these values suggest about the relationship between the variables?
- Using complete sentences, interpret the P value(not the F test statistic) value in the ANOVA table. What does this value suggest about the quality of the simple regression model you generated?
- Using complete sentences, interpret the p-value in the Coefficient table for the explanatory variable. What does this value suggest about the contribution of the explanatory variable to the predictability of the response variable?
- Using complete sentences, interpret the unstandardized beta in the Coefficient table for the explanatory variable.
- Using complete sentences, interpret the standardized beta in the Coefficient table for the explanatory variable.
- Use Excel to generate the residuals for your regression model. Review this source of performance metrics for regression. Construct Excel formulas and use them in your Excel spreadsheet to calculate the MAE and the RMSE. Please DO NOT submit your list of residuals. Do report your MAE and RMSE and the interpretations. Report your results using the following table. APA format accordingly
| Regression Performance Metrics | Value | Interpretation |
- Use the Regression Plots feature of JASP, generate a residuals vs predicted plot , a residuals histogram, and a Q-Q plot standardized residuals. Copy and paste the plots and ensure that they are correctly APA formatted. Use the plots to perform a regression usage assumption check. State whether your plots support the assumptions of independence, normality, and equal variance. Explain
- If it appears feasible to do so, use your JASP output to report and write out the potential Simple Regression equation. Be sure to use the variable names when writing the equation. If it does not appear feasible to report the simple regression equation, using complete sentences and explain why.
