- #1
meowmix
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I suck at probability. I can't think of ways of understanding any problems that involve probability. Here's the problem I'm currently stuck on:
So the first thing I did was make it a little easier for me to understand by rewriting the table in terms of frequency:
Now I've thought of a method for going about solving the problem but it doesn't work. Isn't it correct that P(A or B) = P(A) + P(B)? So I figured that the answer would be P(VermillionEyes or MiniatureWings or Both) = P(VermillionEyes) + P(MiniatureWings) + P(Both). That would be 154/300 + 157/300 + 151/300. BUT THIS IS OBVIOUSLY WRONG SINCE IT GOES PAST 300/300!
How do I do this? Why is the P(A or B) = P(A) + P(B) thing not working?
In a genetics experiment, the researcher mated two Drosophila fruit flies and observed the traits of 300 offspring. The results are shown in the table.
What is the probability that the fly has either vermillion eyes or miniature wings, or both?Code:WING SIZE EYE COLOR Normal Miniature Normal 140 6 Vermillion 3 151
So the first thing I did was make it a little easier for me to understand by rewriting the table in terms of frequency:
Code:
WING SIZE
EYE COLOR Normal Miniature
Normal 4/15 1/50
Vermillion 1/100 151/300
Now I've thought of a method for going about solving the problem but it doesn't work. Isn't it correct that P(A or B) = P(A) + P(B)? So I figured that the answer would be P(VermillionEyes or MiniatureWings or Both) = P(VermillionEyes) + P(MiniatureWings) + P(Both). That would be 154/300 + 157/300 + 151/300. BUT THIS IS OBVIOUSLY WRONG SINCE IT GOES PAST 300/300!
How do I do this? Why is the P(A or B) = P(A) + P(B) thing not working?