he number of typographical errors in a document follows a Poisson distribution with a mean of 4 errors per page. Let X represent the number of errors on 2 pages. Find $\sigma _ { x ^ { * } }$
A) 2.8
B) 8
C) 4
D) 3.8

Question

he number of typographical errors in a document follows a Poisson distribution with a mean of 4 errors per page. Let X represent the number of errors on 2 pages. Find $\sigma _ { x ^ { * } }$
A)  2.8 
B) 8
C) 4
D)  3.8

Quizplus · Accepted Answer

The standard deviation of a Poisson distribution is the square root of its mean. For 2 pages, the mean number of errors is 2*4 = 8. The standard deviation, $\sigma$, is the square root of 8, which is approximately 2.8.

He Number of Typographical Errors in a Document Follows a Poisson