Randomly select 4 females from a study. a)calculate the probability that at least half of the
sample report coughing more than three times a day. b) Use binomial distribution to
approximate the probability from part a. Solve and explain. Here is four random females
numbers if it matters 2,3,3,3
Solution
a) P = 0 as none have coughing more than 3 times a day
b) using binomial distribution the
P = 4C2 P( >3 )^2 P( <= )^2 + 4C3 P( >3 )^3 P( <= )^1 + 4C4 P( >3 )^4 P( <= )
but P( > 3 ) = 0
Hence P = 0