Question

Problem 10) A fair coin is tossed 20 times. A fair coin means that the probability of getting a head is the same as the probability of getting a tril. Let X be the number of coins of getting head. Note that there are only two possible outcomes: getting head or tail after tossing the coin X follows a binomial distribution with n =20, p=0.5. Answer the following questions (Question) Find PX-17).

Answer 1

Given,

n = 20

p = 0.5

A) find the P(X = 17)

We can find out the probability using the formula or technology.

Let's use excel for finding the probability.

Use the following excel command.

= BINOM.DIST(X, n, p, 0)

= NORM.INV(17, 20, 0.5, 0)

We will get, P(X = 17) = 0.001087