Question

A die is rolled 23 times and the number of twos that come up is tallied. If this experiment is

repeated many times, find the standard deviation for the number of twos.

O 1.8

O 19.2

O 5.8

O2.4

Answer 1

1.8

Explanation:

Assume this experiment as a binomial distribution with the probability of success (rolling a two) being 1/6, the probability of failure (not rolling a two) being 5/6 and that the number of trials is n =23.

The standard deviation for a binomial distribution is defined by:

`\sigma = \sqrt {n*p(1-p)}\\\sigma = \sqrt {23*(1)/(6) (1-(1)/(6))}\\\sigma = 1.8`

The standard deviation is 1.8.