Question

Statistics held by the Road Safety Division of the police show that 78% pf drivers being tested for their license pass at thr first attempt has Binomial distribution. If a group of 120 drivers are tested in one centre in a year, calculate a) the mean and standard deviation number of the drivers pass at the first attempt b) the probability that more than 99 pass at the first attempt by using Normal Approximation

Answer 1

Solution:

We are given:

a) The mean and standard deviation of the drivers pass at the first attempt is:

b) We are required to find:

Now using the continuity correction factor, we have:

Using the z-score formula, we have:

Now using the standard normal table, we have:

Therefore, the probability that more than 99 pass at the first attempt by using Normal Approximation is 0.0968