Answer:
b) 0.2961
c) 0.2251
d) Mean = 11.25, Standard deviation = 1.667
Step-by-step explanation:
We are given the following information:
We treat trucks undergoing a brake inspection passin as a success.
P( trucks undergoing a brake inspection passes the test) = 75% = 0.75
a) Conditions for binomial probability distribution
- There are n independent trial.
- Each trial have a success probability p
- The probability of success is same for all trials.
Then the number of trucks undergoing a brake inspection follows a binomial distribution, where
where n is the total number of observations, x is the number of success, p is the probability of success.
Now, we are given n = 15
b) P(proportion of groups will between 8 and 10 trucks pass the inspection)
We have to evaluate:
c) P( exactly 3 trucks fail the inspection)
p = 0.25
d) Mean and standard deviation