Question

Suppose the random variable X has the uniform distribution on the integers 10,11,12

......,30 Find probability that X is the prime number

Answer 1

There are 6 prime numbers between 10 and 30 inclusive (11, 13, 17, 19, 23, 29).

$P(X=prime\; number)=\frac{6}{21}=\frac{2}{7}\approx 0.2851.$