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    Test & Control File Selection - Help

    Thanks again for your continued response, i do appreciate it and it is helping. So are you saying 1- it's not bad practice to sort on the identified key variable and select the test records using every 2nd record and that using Stratified Sampling is however a better method? 2- And, with...
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    Test & Control File Selection - Help

    _____________________________ Hi obh, yes i believe you are referring to stratified random samples which is one of my options. As to why every second record - I am however the whole prospect file into two 50% files therefore sorting on my key variable (say age) and taking every 2nd (even)...
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    Test & Control File Selection - Help

    That is in essence my question yes. Is it valid and correct to force them to be similar (i.e sort on key variable and take every 2nd record as the test) or does the potential bias introduced mean this is never recommended and Pure Random samples or Stratified Random samples are always...
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    Test & Control File Selection - Help

    Thanks Obh, I'm not sure i totally understand your points but i can answer your question: I am comparing the means of a key variable within the test & control files to make sure the files are not significantly different OR they are similar enough to accept that these differences are normal and...
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    Test & Control File Selection - Help

    Can anyone help at all please?
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    Test & Control File Selection - Help

    Hi all I hope all is great with everyone. I'm new on here so sorry to get straight down to my query and hope that someone might be able to point me in the right direction. Thank you. So: I have a prospects direct mail file and I'm testing a new message, (One change). To ensure it’s the...