An auditor has reviewed the financial records of a hardware store and has found that its billing errors follow a normal distribution with mean $0 and standard deviation $1.
- What proportion of the store's billings are in error by more than $1?
- What is the probability that a billing represents an overcharge of at least $1.5
- What is the probability that a customer has been undercharged from $0.5 to $1.5?
- Of the extreme undercharges, 5% would be at least what amount?