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Homework Help: Chi Square Analysis of Phenotype Problem

  1. Feb 26, 2010 #1
    Parental Pheotypes

    Long x Short


    All Long

    F2 Phenotypes

    787 long, 277 short

    1. What is the expected value for the recessive phentotype of the cross Long versus Short

    787+277= 1064

    I did 787/1064= .739 Rounded up to .74 For Long
    277/1064= .26 for Short

    .74x1064= 787.36 Is the Expected value for Long. But this answer is somehow wrong in the system. I'm just trying to see if the system has an error because I don't see how it can be wrong.

    2. What is the Chi Square Sum (rounding to 3 significant figures) for Long versus Short cross.

    Long- (787-787.36)^2/787.36= 1.64E-4
    Short- (277-276.64)^2/276.64= 4.68E-4

    Add those number and I get 6.32E-4 which seems very wrong.
    Last edited: Feb 26, 2010
  2. jcsd
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