Use a Chi-square test to determine whether the data below fit a Mendelian patter
ID: 84679 • Letter: U
Question
Use a Chi-square test to determine whether the data below fit a Mendelian pattern of inheritance. State your specific null hypothesis for this experiment and give Chi squared calculated and Chi squared table values. State whether you accept or reject this null hypothesis and state why. An experiment to determine the inheritance of flower color in snap dragons, you crossed two plants with pink flowers. You know that one gene controls flower color. FOR CREDIT 84 plants had red flowers, 172 had pink flowers, 78 had white flowers.Explanation / Answer
The mendelian pattern of inheritance states that the ratio for incomplete dominance is 1:2:1, therefore the null hypothesis is the ratio of red:pink:white flowers is not 1:2:1.
Total no of flowers is 84+ 172 + 78 =334
Therefore the chi square table could be made like this:
The expected numbers for each color can be calculated as follows- 1/4 * 334 for red and white and 1/2 * 334 for pink.
Now the total of the last column is value of chi square : 0.002 + 0.15 + 0.36 = 0.512 or 0.51
Now the degree of freedom is no of classes - 1
No of classes here are 3 therefore it is 3-1= 2
In the chi square table this value is equal to 5.99 since our calculated value of chi square is less than tabulated value, we accept our null hypothesis which means that the red pink and white flowers are not in 1:2:1 ratio.
Class observed expected o-e (o-e)^2 (o-e)^2/e Red 84 83.5 0.5 0.25 0.002 Pink 172 167 5 25 0.15 White 78 83.5 -5.5 30.25 0.36Related Questions
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