Question

Stats help please?

Answer 1

ohh ok so would it be .6+.3= .9-.3 = .6 ?

Answer 2

two equations you might need

P( A or B) = P(A) + P(B) - P(A & B )
P(A & B ) = P(A) * P( B| A )

also its true that (by symmetry)

P( A & B ) = P(B) * (PA|B)

Answer 3

we are not given P(A & B) in the problem explicitly, but we can derive it.

Answer 4

yea, but i had to find it in the last problem i had to do and found out it was .3 so thats why i used it this time, i could be wrong though

Answer 5

so lets make a formula for P(A or B) , when conditional probabilities are given instead of joint probability, using a substitution.

we have two formulas:

P( A or B) = P(A) + P(B) - P(A)*P(B|A)
P( A or B) = P(A) + P(B) - P(B)*P(A|B)

Answer 6

in our problem we must use this one, since P(B|A) is given:
P( A or B) = P(A) + P(B) - P(A)*P(B|A)

Answer 7

oh ok awesome so i got: .6+.3-.6(.5)= .9-.3= .6

Answer 8

yes thats correct

Answer 9

ok thanks!