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Question : VLookup (or another method like it)....
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Hello Experts,
I'm taking a class covering "Orthogonal Designs". To set up a template for an "interaction table", I need some help with the (potenitally) VLookup method... or something like it.
As they say, "pictures are worth a thousand words." The same holds up for this problem. I think the attached XLS will be somewhat self-explanatory.
Quick recap of the XLS though:
1. I have three variables (A, B, C). We apply the code method to make them "mathematically independent". see 1st (top) table in the XLS.
2. The second tables has the same structure. Here, I "hand jammed" the results of the interactions. AND THIS IS WHAT I NEED SOME HELP WITH. Instead of entering the calculated values manually, I want to compute them.
Examples for computation:
a. Given the 3 variables A, B, and C, there is "interaction" between "AB", "AC", "BC", and finally "ABC".
b. To compute the value for AB, I simply look up the value for A and B in the first experiment (row value #1). I find "-1" and "-1", respectively... thus, AB = +1
Other Info:
- I do NOT want to show a positive 1 as "1". I want to show it as "+1".
- Similarly, I do NOT want to show a negative 1 as e.g. "(1)". I want to show it as "-1".
- Therefore, the following custom number format "+0;-0" must be applied.
Final twist:
I need to make sure that my solution is somewhat flexible. I may have to add a 4th variable (D) to the problem. That would generate additional interactions such as "AD", "BD", "ABCD"... and probably more.
So, my question... using the required format of "+0;-0" (showing -1, +1) and the required flexibility for additional variables, does anyone know how I can compute the interactions values in Excel?
Thousand thanks in advance,
EEH
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Answer : VLookup (or another method like it)....
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Here is a sample workbook showing the formulas in action.
Brad
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