Question

You are testing 100circuit boards. each passes with 70% probability and the trials are independent. let x be the random variable for the number of circuit boards that pass. what is the mean of x?

Answer 1

Using the binomial distribution, where the number of trials is n and the probability of success is p, the mean is equal to np.
Therefore the mean of x in the question is 100 * 0.7 = 70.
The answer is: 70 circuit boards.