Question

Twelve percent of the population is left handed. Approximate the probability that there are at least 20 left-handers in a school of 200 students. State your assumptions.

Answer 1

Explanation:

We would assume a binomial distribution for the handedness of the population. Let x be a random variable representing the type of handedness in the population. The probability of success, p is that a randomly chosen person is left handed only. Then probability of failure is that a chosen person is not left handed only(right handed only or both).

p = 12/100 = 0.12

number of success, x = 20

n = 200

the probability that there are at least 20 left-handers is expressed as P(x ≥ 20)

From the binomial probability calculator,

P(x ≥ 20) = 0.84