# Chi-squared followup

13/04/18 10:52

## Chi-squared followup.

Because I expected to get farther before the test, I have blog posts that go into the things I meant to cover. So, I'll move them closer to the top so you can see them (the will be just below this one).

I made a dumb mistake as you were walking about the door.

I gave you the wrong definition of "pleiotropy." (what I gave you was the definition of "epistasis," another new term. I have them properly described/defined, in the blogs below. Please make note of my mistake if you wrote it into your notes.

Below are some data to practice some more chi squared calculations, if you would like to do them.

This is a Dihybrid cross, meaning AaBb x AaBa. That means the expected results are 9:3:3:1. That won’t be what you get.

Cage 17 is the F1 dihybrid. Cages 12 and 16 are their because the were the source of the P1 generation.The remaining three cages, 18, 21 and 25 are just increasing numbers of offspring. Try performing a chi-square for 18, 21 and 25. It’s pretty striking how the size of the data set makes such a difference. There is a chi-square table below to assess the probabilities. For the homework, submit the chi-square value for each cage. What are the “Parental” types you expect to see more frequently if the genes are linked. Do you think the genes are linked? Explain your reasoning.