The KW water is provided to approximately 750,000 people, who are served through more than 362,000 accounts. All accounts are metered and billed monthly. the probability that an account has an error in a month is 0.001, and accounts can be assumed to be independent.
a- what is the mean and standard deviation of the number of account errors each month?
b- approximate the probability of fewer than 350 errors occur in a month.
c- approximate a value so that the probability that the number of errors exceeds this value is 0.05.
The solution provides step by step method for the calculation of probability using the Z score. Formula for the calculation and Interpretations of the results are also included.