In eight throws of a die 5 or 6 is considered a success, find the mean number of successes and the standard deviation.

Options

A. `(8)/(6), (16)/(9)`
B. `(8)/(3),(4)/(3)`
C. `(4)/(3),(4)/(3)`
D. `(4)/(3

Answer

B

Explanation

5 or 6 is success .
`therefore p = (2)/(6) = (1)/(3)`
`therefore q = 1 - (1)/(3) = (2)/(3)`
n = 8
`therefore` Mean = np `=8((1)/(3)) = (8)/(3)`.
Standard deviation ` = sqrt(npq) = sqrt(8((1)/(3))((2)/(3)))`
` = sqrt((16)/(9)) = (4)/(3)`