Question

Consider the binomial random variable x with n = 30 and p = 0.85.
(a) Find the mean. (Give your answer correct to one decimal place.)
25.5 .

(b) Find the standard deviation. (Give your answer correct to two decimal places.) 30.85

Answer 1

Mean is correct.

Standard deviation = sqrt(npq))

sqrt(30* .85 *.15) = 1.96

Answer 2

Thank you I left out the .15 and sqrt. I have a lot of problems with the standard deviation and not sure why. Is there a simple formula to use????