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Math Help - Combinations Question

  1. #1
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    Combinations Question

    I have required fields to fill in before somebody clicks submit in a computer program, but I want to tell our testing team that we need to test to make sure the program does not submit unless all required fields are filled in. But, I want to test all of the combinations of the required fields, except for the combination where I fill all the fields in because that should always work.

    Is this expressed as

    n choose (n-1), where n is the number of required fields?

    If so, do you know if there is any software program we could use that will generate a true/false table of combinations if we supply the names of the variables to automate a list for us so that this can be printed out? It would have to be something free, but I just need a basic program.

    Thanks
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  2. #2
    MHF Contributor
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    Hello applewine

    Welcome to Math Help Forum!
    Quote Originally Posted by applewine View Post
    I have required fields to fill in before somebody clicks submit in a computer program, but I want to tell our testing team that we need to test to make sure the program does not submit unless all required fields are filled in. But, I want to test all of the combinations of the required fields, except for the combination where I fill all the fields in because that should always work.

    Is this expressed as

    n choose (n-1), where n is the number of required fields?
    No. This assumes that all the required fields are filled in except 1. You need to test for 0, 1, ..., (n-1) fields filled in. The total number of possibilities is therefore
    \sum_{i=0}^{n-1}\binom ni = 2^n -1
    If so, do you know if there is any software program we could use that will generate a true/false table of combinations if we supply the names of the variables to automate a list for us so that this can be printed out? It would have to be something free, but I just need a basic program.

    Thanks
    No, I don't. Have you considered trying to set something up in Excel? It handles True/False values quite neatly, with Boolean operators AND, OR and NOT.

    Grandad
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