# Probability HW verification

Discussion in 'Probability and Statistics' started by borogirl09, Oct 9, 2012.

1. ### borogirl09

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Records of student patients at a dentist's office concerning fear of visiting the dentist suggest the following: Fear (Elem=.12, Midd=.08, High=.05). Dont fear (Elem=.28, Midd=.25, High=.22). Let F= a student fears the dentist & H= a student is in high school. Find 1. P(H^c), 2. P(F or H), 3. P(F n H^c), and 4. P(F|H). The n in the 3rd probability is the upside down U representing intersection. And determine if F and H are independent. If dependent, indicate direction of dependence.

I just really need someone to check my answers because I am not sure what I got is correct.
1. 1-.27= .73
2. .25 + .27 - .05 = .47
3. .25 +.73 -.78 = .2
4. .05/.27 = .1852
5. Since P(F)= .25 and P(F|H) = .1852 F and H are dependent. I do not know how to determine the direction of dependence.

I mainly have a problem with the intersection and conditional probability questions. I am not sure if I am doing it the right way, and if I'm not, I don't know what I am doing wrong. Any help would be appreciated.

borogirl09, Oct 9, 2012