A major financial services company wishes to better understand its mortgage approval process. In particular, the company is interested in learning about the effects of credit history (good versus fair), the size of the mortgage (<$500,000 versus >$500,000), and the region of the United States (western versus eastern) on the amount of time it takes to get a mortgage approved. The database of mortgages approved in the last year is accessed, and a random sample of five approved mortgages is selected for each of the eight combinations of the three variables. The data are shown in the table
Mortgage Approval Time Study
Credit History Mortgage Size Region Approval Times (Days)
Good <$500,000 Western 59 50 64 62 47
Fair <$500,000 Western 81 58 69 65 74
Good >$500,000 Western 38 52 58 60 65
Fair >$500,000 Western 146 159 133 143 129
Good <$500,000 Eastern 28 26 38 41 21
Fair <$500,000 Eastern 42 53 40 50 64
Good >$500,000 Eastern 49 31 49 42 38
Fair >$500,000 Eastern 106 115 126 118 138
First, conduct an analysis using the following steps:
- Use the data shown in the table to conduct a design of experiment (DOE) in Microsoft Excel in order determine the nature and magnitude of the effects of the three variables on mortgage approval times. What are the key drivers of this process?
- Determine the graphical display tool (e.g., Interaction Effects Chart, Scatter Chart, etc.) that you would use to present the results of the DOE that you conducted in Question 1. Provide a rationale for your response.
- Assess the data sampling method. Our sample contained only five mortgages per combination. Under what circumstances would it have been appropriate to select a larger sample? Is a sample of five mortgages adequate to access the relative magnitudes of the effects of the variables? What sample size would you recommend? What could you learn from a larger sample size? (Hint: Look back at chapter 2, 3, 5, and 6 for discussion of sampling.)
- Provide other variable responses that might be of interest to measure and study. (Hint: If you were getting a mortgage or a loan, what are the two and most important measures of the process you would have to go through?)
- Propose one overall recommendation to the financial services company, based on the DOE, that could help reduce mortgage approval times.