Answer Happy

b) Record your data below. Number of Purple Kernels Observed Number of Yellow Kernels Observed K*X c) Do your data follow the expected ratio for a monohybrid cross? To answer that, you will calculate the chi-square of your results. You will test the null hypothesis that there is no significant difference between the expected and observed result. To calculate x2, first determine the number expected in each category. For example, if the ratio is 3:1 and the total number of observed individuals is 1,000, then the expected value should be 750 dominant and 250 recessive. The observed value would be the actual amount you counted from the corn cob picture above.

Step 1: Record the number of phenotypes you observed in the F2 generation: Observed Number of kernels (o) Phenotype Purple Yellow Total Step 2: Determine the ratio of phenotypes you expected in the F2 generation of a monohybrid cross: Phenotype Purple Yellow Expected Ratio Phenotype: Observed Value (o) Expected Value (e) H Step 3: Calculate the x2 value by filling out the table below. First row are the observed number of kernels of each color (o, from the first table above), Second row are the expected number of kernels for a F2 generation in a monohybrid cross (e, from the table above). The third row is the difference between o and e). The fourth row is the values of the third row squared. And, finally, to obtain the values in the last row, divide the values on the 4th row by the values on the 2nd row. Purple Deviation (d) = o-e Deviation (²) d¾le To obtain the x value: add all de values: Total kernels (Both Colors) 15 Expected Number of kernels (e) Yellow

Step 4: Determine degrees of freedom to assess the significance of x² value. Number of Possible Phenotypes Degrees of Freedom -1 1 2 3 4 = Step 5: Determine whether to accept or reject your hypothesis. Find the probability that the deviation of the observed values from the expected values was a chance occurrence. Look up your degrees of freedom in the table below. Find where your x² value falls in that ROW. Degrees of Freedom Probability (p) 0.95 0.90 0.80 0.70 0.50 0.30 0.20 0.10 0.05 0.01 0.001 0.004 0.02 0.06 0.15 0.46 1.07 1.64 2.71 3.84 6.64 10.83 0.10 0.21 0.45 0.71 1.39 2.41 3.22 4.60 5.99 9.21 13.82 0.35 0.58 1.01 1.42 2.37 3.66 4.64 6.25 7.82 11.34 16.27 0.71 1.06 1.65 2.20 3.36 4.88 5.99 7.78 9.49 13.28 18.47 Probability value = If the probability is 20.05, then you can accept your null hypothesis. If the probability is ≤0.05, then you can reject your null hypothesis. In other words, the probability value is the probability that the deviation of the observed from that expected is due to chance alone (no other forces acting). In this case, using p > 0.05, you would expect any deviation to be due to chance alone 5% of the time or less. In any case, a scientist would then run more tests to see if the results were repeatable. Can you accept or reject your null hypothesis?