WIN MINIRANKS! WoW Thats Really Swell!

In the spirit of Christmas and the fact that I have a stats final tomorrow, I propose a question to the sythe community and whoever can solve it first and explain it below will win one



Phytophthora infestans (P. infestans) is the oomycete that causes potato blights. Suppose that 8% of potato plants have a P. infestans infestation. A botanist develops a new test for early P. infestans detection. This test has a 12% false positive rate, and a 5% false negative rate.

Given that a randomly selected potato tests positive for P. infestans, what is the probability that the potato actually has P. infestans?

 

8% . . . . .

 

cbf doing stats.

guessing: 5%

 

i did this quickly, but is it 5.81818%?

 

.08*.95/(.92*.12+.08*.95)~40.77%

8%*95% of plants test true positive and another 92%*12% will produce a false positive

 

Video got it, closed.