'2. sample dhitSquiireProhl'em ' Problem: An ear ofc'om' has a total of 381 grains, including 216 Purple & Smooth, 79 Purple 1 ind 21 Yellow}; Shnmken."l'hese phenotypes and numbers are entered in Columns 1 and 2 of the follow nutritive Hypothesis: This ear of com was produced by a dihyhrid cross (PpSs x PpSs) involving two pairs'of ulng in a theoretical (expected) ratio of 9:3:3: 1. See dihybrid cross in Table 1. ' Vbj'eeve: Test your hypothesis using chi square and probability values. In order to test your hypothesis you must ll ' fbllowing Table 2. ' 'k V liFor the observed number (Column 2), enter the number of each grain phenotype counted on the car of corn. , . 1 i r 2.-To calculate the observed ratio (Column 3). divide the number of each grain phenotype by 21 (the grain phenotype with thel number of grains). , , 5 For the expected ratio (Column 4), use 9:323: l , the theoretical ratio for n dihybl'id cums. The fractional ratios for these 9/16, 3/16. 3116 and 1/16. 4. Th calculate the expected number (Column 5). L phenotype. S. In the lest column (Column 6), , number (Column 5), square this multiply the number of each grain phenotype by the expected fraction!\" ttti for each grain phenotype take'the observed number of grains (Column 2) Vandsubht the'ex difference, and then divide by the expected number (Column 5). Round off to three decimal l ' 5. To calculate the chi square value, add up the four decimal vulueslu the lust column (tinnitus 6). pected Expected xp Ratio Numhtlr + it at) (Column 5) um llmma - 381 x 3/16 2 71 64/71 5 0.901 381x1/16 Z4 ivy-0.37! ."- m u: w l 5 Table 2. Chi Square Data Degrees mmoit Number of phenotypes - l. in this problem the number of phenotypes (d0 is three (4 - l = 3). In the following Table 3 you need to locate the number in row three that 8. Probability Value: In the following Table 3, nd the number in row three that is closest to your chi square value of 1.80;'In ' (shaded in yellow) is the closest number. Then go to the top of the column and locate your probability value. In this case the 13' mile that lines up with 1.85 is .60 (shaded in yellow). This number m suns that the probability that your hypothesis is none til W. The pmbshillty that your hypothesis is incorrect is 0.40 or 40 percent. ' , is four; therefore, the degrees tit is nearest to your chi square val Good Fit Between Ear & Data ' f nnmnnnm i Ila-um ' na-maamw ~ HIM-ENE ' ' t 'mm ' \"#31