Discussion Section michelle wk 6 p1

Discussion Section michelle wk 6 p1 - o All the numbers...

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BICD-100 Genetics Ghiara Spring 08 Week 6- Tuesday Chi-Squared Analysis - Why do we need to use a Chi-Squared Analysis? - How to use it: o Collect data and categorize the classes. o Collected data is observed values. o Need to find expected values. How would you do this? o Calculate Chi-squared value. - = Expected Expected Observed 2 2 ) ( χ o Calculate the df (degrees of freedom). 1 - = n df o Use chi-squared and df on chart (Table 3.4 or 3.2 in text book) - Critical Value Chi-Squared value = 5.9991, P = 0.05. This is the “cut-off range” assumed in biological experiments. o If below Critical Value data is accepted, proves hypothesis is correct, and errors are most likely due to chance. o If above Critical Value data is not accepted; hypothesis is wrong, and errors are significant (there is something significant going on with the genes) - How to read the Chi-Squared Table: o Df = degrees of freedom (obviously) o P = probability of that particular chi-squared value of the experiment to occur in that df.
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Unformatted text preview: o All the numbers checkered all over the table = chi-squared values, NOT probabilities. 35) J.A. Moore investigated the inheritance of spotting patterns in leopard frogs. The pipiens phenotype had the normal spots that give leopard frogs their name. In contrast, the burnsi phenotype lacked spots on its back. Moore carried out the following crosses, producing the progeny indicated. Parent Phenotypes Progeny phenotypes BICD-100 Genetics Ghiara Spring 08 Week 6- Tuesday Burnsi x burnsi 39 burnsi, 6 pipiens Burnsi x pipiens 23 burnsi, 33 pipiens Burnsi x pipiens 196 burnsi, 210 pipiens a) On the basis of these results, what is the most likely mode of inheritance of the burnsi phenotype? b) Give the most likely genotypes of the parents in each cross. c) Use a chi-square test to evaluate the fit of the observed numbers of progeny to the number expected on the basis of your proposed genotypes....
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This note was uploaded on 01/25/2011 for the course BICD 100 taught by Professor Nehring during the Spring '08 term at UCSD.

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Discussion Section michelle wk 6 p1 - o All the numbers...

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