A recent study of the hourly wages of a company's maintenance crews revealed that the average hourly wage was $16.50; and the standard deviation, at $3.50. If we chose a member of these teams at random:

1) What would be the probability that he earns between $16.50 and $20 per hour?

2) What would be the probability that he earns more than $20 per hour?

3) What would be the probability that he earns less than $15 an hour?

4) What would be the probability that he earns more than $16 but less than $18.5 per hour?