Complete all the writing parts of this assignment:
The data you will use for this week’s homework is hypothetical research data on wrinkle resistance cotton cloth. In this case, a research chemist wants to understand how several predictors are associated with the wrinkle resistance of cotton cloth. The chemist examines 32 pieces of cotton cellulose produced at different settings of curing time, curing temperature, formaldehyde concentration, and catalyst ratio. The durable press rating, which is used as a measure of wrinkle resistance, is recorded for each piece of cotton.
Instructions
Import the data in WrinkleResistance.xlsx file into SPSS
Create variable labels for each variable using the variable descriptions below
Variable
Description
Conc
The setting of formaldehyde concentration
Ratio
The catalyst ratio
Temp
The temperature that the sample was exposed to
Time
The amount of time that the sample was exposed to test conditions
Rating
The rating of wrinkle resistance
Save the file as WrinkleResistance.sav
Estimate a multiple regression model that could be used to predict the wrinkle resistance rating of cotton cloth given data on the four predictor variables. (This means write out a general model using symbols and variable names.)
Create a scatterplot matrix for all the variables.
Conduct a multiple regression analysis (starts with step 3 on page 159). Use the “Forward” method of selection.
Write out the equation for your final model (look about half-way down the first column on page 162).
Using R2 adjusted, calculate the effect size using Cohen’s equation on the bottom of page 156. (Does SPSS do this automatically now?)
Conduct a residual analysis (bottom of page 162).
The write-up needs to include:
An introduction: What is the objective of this study? What is your dependent variable? Independent variables? Who hired you?
Analysis section: What analysis did you do? What is your equation of the model? What is R2 and its interpretation? Cohen’s? Your scatterplot matrix, residual scatterplot, and table similar to 5.3 or 5.4 would be a part of this section. You also need to include the test statistics and p-values for all of the predictors included in final model.
Conclusion: This should be non-statistical. Anyone should be able to read this section and understand your conclusions. Also can include what you would recommend for future studies and any problems you encountered.
Deliverables:
One Word doc. Include all syntax at the end of the document.
