## Monday, May 24, 2010

### Statistics Question on Probability?

The employees of a company were surveyed on questions regarding their educational background and marital status. Of the 600 employees, 400 had college degrees, 100 were single, and 60 were single college graduates. The probability that an employee of the company is single or has a college degree is: The answer is .733 How the hell do you come up with that??? I have a feeling the answer is right in front of me...please help

Statistics Question on Probability?
400 employees have college degrees. Of these, 60 are single. That leaves 40 employees who are single but don't have a college degree. So there are 440 employees that have a college degree and / or are single.

440 / 600 = .733

So you don't want to count those again, so you have to subtract them out of the sum of the number who have college degrees and the number who are single (since you're counting them twice)

400 + 100 - 60

500 - 60

440

440/600 = .7333
Reply:For any two events A and B

P( A OR B ) = P(A) + P(B) - P(A AND B)

in this case we have

P( single OR college)

= P(single) + P(college) - P(single AND college)

= 100/600 + 400/600 - 60/600

= 0.7333333

B = Single

P(A or B) = P(A)+P(B)-P(A %26amp; B)

=400+100-60=440

440/600 = 0.7333