The number of hours spent working per week for US adults is normally distributed with a mean of 40 and a standard deviation of 4. Calculate z-scores first and then look up the areas (percentages) from the table of z distributions.

1. What percentage of adults work less than 30 hours per week? (3 points)
2. What percentage works more than 50 hours? (3 points)
3. What percentage spends between 32 to 44 hours? (4 points)
4. If we picked an adult at random, what is the probability that she or he would spend more than 45 hours per week? (3 points)
5. If we picked an adult at random, what is the probability that she or he would spend less than 20 hours per week? (3 points)