More Chi Square Practice Problems AP Biology 1. In peas, yellow seeds are dominant over green seeds. In a cross between two plants both heterozygous for seed color, the following was observed: yellow green 1624 What do you predict the expected phenotypic ratio to be? State a NULL h othesis for this qxperimen . ccos Phenotype Observed (o ... discuss how these explained the data. Part (b), reflecting two objectives from Laboratory #7 in the AP Biology laboratory manual, asked students to use a chi-square statistical test to support the hypothesis formulated for the data in the F2 generation. This required a correct hypothesis, use of the formula, calculation, and interpretation.

Comparing Correns’s results to Tschermak’s results using the Chi square test: x In both experiments, the 6 F2 was less than the critical value at 0.05, so H 0 was accepted. x In Correns’s experiment, the 6 F2 value was 0.220, which means that the probability of his distribution occurring by chance was between 0.45 and 0.15. chi-square D e n s i t y Distribution Plot Chi-Square, df=10 Test Statistic ∑ ( ) P-value The larger the value of the test statistic, the stronger the evidence against the null hypothesis. The P-value of a test is: ( ), or the tail area to the right of the calculated test statistic.