Question

"Suppose that past records indicate that the probability is 0.04 that a new car will need repair in the first 90 days of use. What is the probability that, for the next 500 cars sold, between 15 and 30 cars need a repair? (including 15 and 30)"

-Please show Excel commands

Answer 1

The number of cards that would need repair out of the 500 cars sold is modelled here as:

The probability required here is computed as:

We use the Cumulative probability function for binomial distribution here to get the required probability as:

= binom.dist(30,500,0.04,TRUE)-binom.dist(14,500,0.04,TRUE)

This is the excel function required.

Note that the output here is

0.88799525

Therefore 0.88799525 is the required probability here.