8.1b Mean, Variance and Standard Deviation of a Binomial Distribution
2. Determine the mean, variance and standard deviation of binomial distribution
If X is a binomial discrete random variable such that X~B (n, p),
Mean of X,
Variance of X,
Standard deviation of X,
A Football club organises a practice session for trainees on scoring goals from penalty kicks. Each trainee takes 8 penalty kicks. The probability that a trainee scores a goal from a penalty kick is p. After the session, it is found that the mean number of goals for a trainee is 7.2.
Find the value of p.
Mean = np
np = 7.2
8p = 7.2
p = 0.9
X is a binomial random variable such that X ~ B (n, p). If its mean and standard deviation are 90 and respectively, find the value of p and of n.