chi square questions

Question

Chi Square

Consider the scenario where one parent is type AB blood and the other parent is heterozygous for type B blood. A sample of 150 couples collectively produced a total of 38 children with type A blood, 117 children with type B blood, and 38 children with type AB blood. 

1. Determine the expected ratio of blood types for offspring produced by the above cross.
2. Calculate a chi-square value for this example in the space below. 
3. Could the difference in the actual outcome relative to the expected ratio be due to chance variation or is it a result of some other factor? 
4. What conclusion(s) could you draw from the data?

Answer 1

First create the punnet square and then calculate the ratio. See if the ratio matches to what you have.

in this case let see what i get it says 50% B group and 25% each. so we should have had 96.5 children with B and 48.25 of the other two blood group.. The chi square value is 8.7 calculated by using the excel, which is greater than the critical value of 5.991 so the null is rejected and this is not expected and not by chance as p<0.05. Its hard to say what's causing the B to be more prevalent