To assess Mendel's law of segregation using tomatoes, a true-bree...

Question

To assess Mendel's law of segregation using tomatoes, a true-breeding tall variety (SS) is crossed with a true-breeding short variety (ss). The heterozygous F₁ tall plants (Ss) were crossed to produce two sets of F₂ data, as follows.

Set I Set II _
30 tall 300 tall
     5 short      50 short

Using the X² test, analyze the results for both datasets. Calculate X² values and estimate the p values in both cases.

Accepted Answer

Hey everyone. Let's take a look at this question. Together. The trait for round seed is dominant over wrinkled peas and yellow pea color is dominant over green. A di hybrid cross between two hetero sickos pea plants is performed and the following fanatic frequencies are observed. We have 800 round yellow peas, 241 round green peas, 220 wrinkled yellow peas and 66 wrinkled green peas. Based on the above results. The statistical value calculated by the chi square test is as followed. So we know that the formula for a chi squared test is X squared equals the sum of the observed minus expected values squared, divided by the expected values. So let's go ahead and set up a chart of all of our observed and expected values for this dye hybrid cross. So here we have our chart and we can go ahead and fill it out based on the information that is provided in the question. So the observed frequencies of round yellow, round green, wrinkled yellow and wrinkled green are 800 round yellow, 241 round green, 220 wrinkled yellow and 66 wrinkled green. With a total of 1327 total fanatic pick frequencies observed. So to find the expected value, we take the fanatic ratio of the two hetero, six p plants that are crossed and multiply that by the total number that we calculated. So the fanatic ratio is a 9331. Because we crossed to hetero six p plants. And then our total number of 1327 for the expected of round yellow. We have nine out of 16 that we take nine out of 16 and multiply it by 13 to 7 And we end up with 746. We do the same for the other three. So we have three out of 16, 3 out of 16 and one out of 16 all multiplied by the total number of 1327 seven. And we end up with 249, 249. And then lastly we have 83 hour observed minus expected values are as follows and our observed minus expected to the power of two divided by the expected value is as follows as well. And so we are trying to figure out what X squared is equal to which is the sum of the observed minus expected squared divided by the expected which is 10.86 because we add all of these values together and we end up with 10. which we can then round up to 10.9 which is answer choice C. The correct answer. Because when we do the chi square test for the following fanatic frequencies we end up with 10.9 as that statistical value calculated by the chi square test. So that makes answer choice C. The correct answer. I hope you found this video to be helpful, Thank you and goodbye.

Key Concepts

Mendel's Law of Segregation

Chi-Square Test (X² Test)

P-Value

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