Question

Suppose that you are in a class of 31 students and it is assumed that approximately 18% of the population is left-handed. (Give your answers correct to three decimal places.) (a) Compute the probability that exactly five students are left-handed. (b) Compute the probability that at most four students are left-handed. (c) Compute the probability that at least six students are left-handed.

Answer 1

Solution:

We are given that,

n= sample size = 31

p = probability of success = 0.18

a) P( x = 5 ) = ______?

Using excel formula, =BINOMDIST(5,31,0.18,FALSE)

P( x = 5 ) = 0.1844

b) P( x 4 ) = _____?

Using excel formula, =BINOMDIST(4,31,0.18,TRUE)

P( x 4 ) = 0.3211

c) P( x 6 ) = 1 - P( x 5 ) = __________?

Using excel formula, =1-BINOMDIST(5,31,0.18,TRUE)

P( x 6 ) = 0.4945

Done