## Need to know if my answer are correct or no ?

Standard deviation, mean, variance, z-scores, t-tests, etc.
Martingale
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### Re: Need to know if my answer are correct or no ?

so

P(A) + P(B) - P(A $\cup$ B) = P(A). P(B)

0.5 + P(B) - 0.8 = 0.5 P(B)

P(B) - 0.3 = 0.5 P(B)

P(B) = 0.5/0.3 (Is this correct?)
How can P(B) = 0.5/0.3? That number is greater than 1!!

from my work can u please point out the mistake
start from here...
P(B) - 0.3 = 0.5 P(B)

and solve for P(B) again.

zorro
Posts: 28
Joined: Sat Jun 12, 2010 9:26 am
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### Re: Need to know if my answer are correct or no ?

start from here...
P(B) - 0.3 = 0.5 P(B)

and solve for P(B) again.

P(B) - 0.3 = 0.5 P(B)

P(B) - 0.5 P(B) = 0.3

P(B) [ 1 - 0.5 ] = 0.3

P(B) 0.5 = 0.3

P(B) = 0.3 / 0.5 (Is this correct ?)

Martingale
Posts: 333
Joined: Mon Mar 30, 2009 1:30 pm
Location: USA
Contact:

### Re: Need to know if my answer are correct or no ?

start from here...
P(B) - 0.3 = 0.5 P(B)

and solve for P(B) again.

P(B) - 0.3 = 0.5 P(B)

P(B) - 0.5 P(B) = 0.3

P(B) [ 1 - 0.5 ] = 0.3

P(B) 0.5 = 0.3

P(B) = 0.3 / 0.5 (Is this correct ?)
Yes