Which expressions are equivalent?

Aline on the wall and a line on the floor are skew. always, sometimes, or never?

Monthly water bills for a city have a mean of $108.43 and a standard deviation of $32.09. find the probability that a randomly selected bill will have an amount greater than $155, which the city believes might indicate that someone is wasting water. would a bill that size be considered unusual?

How do you solve a question like this?