Probability and Statistics

[watchkimberly]

Can someone check if I did this right?

I there a relationship between gender and relative finger length? to find out, we randomly selected 452 U.W. Hight School students who completed a survey. The two way table summarizes the relationship between gender and which finger was longer on the left hand (index finger or ring finger). Suppose we randomly select one of the survey respondents. Define events R: ring finger longer and F: female.

A) Find P(R|F). Interpret this value in context.
My answer: 82/212 = 0.3867924 = 38.7
B) Given that the chosen student does not have a longer ring finger, what's the probability that this person is male?Write your answer as probability statement using correct symbols for the events.
My answer: P(male|no longer ring finger) = 45=43/123+95 = 88/218 = 0.40366972 = 40.4

 

[Harry_the_cat]

A. 0.3868 (4dp) is correct. BUT 0.3867924 does NOT equal 38.7. Perhaps you meant 38.7%. You still need to interpret this in context, eg 38.7% of .....

B. Use brackets (45+43)/(123+95).
Now write as a prob statement using correct symbols.
M is male, what is "not ring finger"? There are several notations for the complement of R, sometimes a dash, sometimes a line on top. What do you use?

 

[lucyle992]

Part A) Yes, I wasn't sure. I first wrote 38.7%, and then erased it. Given that the person is a female, the probability that this person has a longer ring finger is 38.7%
Part B) Not a ring, would be R^c . P(m|R^c) = (45+43)/(123+95) = 88/218 = 40.4%
Given that this person does not have a longer ring finger, the probability that this person is male is 40.4%