Question: A company randomly selects accounts for audits, and 10% if the audited accounts are found to contain certain errors. The accounts are audited in batches of 15.

a) Find the mean number of erroneous accounts per batch.

b) find the probability that a batch contains exactly two accounts with errors.

c) find the probability that a batch contains at least two accounts with errors.

d) If one large batch contains 30 accounts, find the probability that there will be exactly 4 accounts with errors.