# Expectation and Variance

• Dec 11th 2008, 10:18 AM
geeko
Expectation and Variance
hey, I have problem solving this question...can anyone explain it to me Plz!

In a group of people the expected# who wear glasses in 2 and the variance is 1.6.
a.) Find the prob that a person chosen at random from the group wear glasses

b.)6 people in the group wear glasses
• Dec 11th 2008, 09:05 PM
mr fantastic
Quote:

Originally Posted by geeko
hey, I have problem solving this question...can anyone explain it to me Plz!

In a group of people the expected# who wear glasses in 2 and the variance is 1.6.
a.) Find the prob that a person chosen at random from the group wear glasses

b.)6 people in the group wear glasses

I'm suspicious of the wording ....... I think the question intends you to treat it as a binomial distribution problem but as currently stated it cannot. If the intent is a binomial distribution, then I'd expect the wording to be along these lines:

Quote:

In group of people chosen at random the expected# who wear glasses is 2 and the variance is 1.6.

a.) Find the prob that only one person in the group wears glasses.

b.) Find the prob that six people in the group wear glasses.
Before I continue I'll wait for a second opinion.