Assuming X is a binomial random variable, what is the mean number?

Question

There is a p=12.5% chance a parked car will have been left unlocked. X is the number of cars left unlocked in a parking lot with a total of 6 cars. Assuming X is a binomial random variable, what is the mean number of unlocked cars you'd find?

 

A hint is: u=E[X]

Answer 1

For a binomial distribution (n Bernoulli trials), μ = np.

 

p = 0.125 and n = 6, this gives μ = 0.75