Question

Find the probability of getting 5 exactly twice in 7 throws of a die.

Answer 1

The repeated tossing of a die are Bernoulli trials. Let X represent the number of times of getting 5 in 7 throws of the die.

Probability of getting 5 in a single throw of the die, p = 1/6

`:. q = 1 - p =1 - 1/6 = 5/6`

Clearly, X has the probability distribution with n = 7 and p = 1/6