A random variable is binomially distributed with n = 16 and π = .40. The expected value and standard deviation of the variables are

The number of tickets purchased by an individual for Beckham College's holiday music festival is a uniformly distributed random variable ranging from 3 to 9.  what is the standard deviation of this random variable?

Let x be a random variable that represents the commute time of teachers in a large rural area. If x is normally distributed with a mean of 64 minutes and a standard deviation of 12.2 minutes, find the probability that a commute time is greater than 70 minutes.

The taxi and takeoff time for commercial jets is a random variable x with a mean of 9 minutes and a standard deviation of 3.4 minutes. Assume that the distribution of taxi and takeoff times is approximately normal. You may assume that the jets are lined up on a runway so that one taxies and takes off immediately after the other, and that they take off one at a time on a given runway. (a) What is the probability that for 35 jets on a given runway, total taxi and takeoff time will be less than 320 minutes? (Round your answer to four decimal places.) (b) What is the probability that for 35 jets on a given runway, total taxi and takeoff time will be more than 275 minutes? (Round your answer to four decimal places.) (c) What is the probability that for 35 jets on a given runway, total taxi and takeoff time will be between 275 and 320 minutes? (Round your answer to four decimal places.) US 12:44 hp DII -> & $ @ 7 8 3. 4 5 i y r W k d m V .. ..