VCU BIOL 310 - Meiosis and Mendel (5 pages)

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BIOL 310 1st Edition Lecture 5 Outline of Previous Lecture Mendelism I Testing agreement of hypotheses and data a Chi Squares b What is a P Value II Mendels tests F2 s of round yellow X wrinkled green Outline of Current Lecture I III Chi squares What are genes and where are they located a Discoveries post Mendel I Chi Squares Working hypothesis if you accept the null you accept the working if you reject the null you must reject the working because there is too much deviation due to chance F2 Progeny round yellow round green wrinkled yellow wrinkled green Obs Exp Exp Num Prop O E 315 9 16 313 2 108 3 16 104 4 101 3 16 104 3 32 1 16 35 3 556 16 16 556 0 portions highlighted MUST be present to get full credit on an exam 54 O E 2 E 4 313 16 104 9 104 9 35 54 d f 4 classes 1 3 DF By inspection P to find P go to the table and look for 54 under the 3 DF Our 975 chi squared 9 Should we accept or reject null hypothesis at the 5 level o Accept the null There is a small amount of deviation because our P value 05 If we accepted the null hypothesis do the results PROVE that the working hypothesis is correct These notes represent a detailed interpretation of the professor s lecture GradeBuddy is best used as a supplement to your own notes not as a substitute o No it doesn t Accepting only confirms that the data is consistent with the hypothesis If we rejected the null hypothesis do the results PROVE that the working hypothesis is incorrect If reject null hypothesis with a P value of 0 04 how often do you expect to reject a potentially valid hypothesis i e theoretically how often would this much deviation be due to random chance alone o About 4 If set rejection cutoff at P 0 01 o Would we accept more or fewer correct hypotheses Accept more null hypothesis and more alternative hypotheses o Would we accept more or fewer incorrect hypotheses Accepting more correct hypotheses would force you to accept more incorrect hypotheses as well Practice Problem Mendel crossed true breeding tall