Pew Research Center surveyed adults that were 18–64 years old and had their own children under age 18 living in their household in 2015 on the amount of time spent on various activities. The results indicated that moms spent an average of 25 hours per week doing paid work (compared to 43 hours per week for dads). Assume the hours per week doing paid work follows the normal probability distribution with a standard deviation of 6.7 hours per week and that these statistics still hold true.

a. What is the probability that a randomly selected mom from this group spent

1. fewer than 18 hours doing paid work this week?

2. more than 18 hours doing paid work this week?

3. between 23 and 30 hours doing paid work this week?

4. between 11 and 19 hours doing paid work this week?

b. Use Excel to confirm the answers in part a.

c. How many of hours of paid work will a mom in this group perform if she is in the 20th percentile?