In a poll conducted by the General Social Survey, 81% of respondents said that their jobs were sometimes or always stressful. Ten workers are chosen at random.

a. What is the probability that exactly 7 of them find their jobs stressful?

b. What is the probability that more than 6 find their jobs stressful?

c. What is the probability that fewer than 5 find their jobs stressful?

d. Would it be unusual if fewer than 4 of them find their jobs stressful?

e. What is the mean number who find their jobs stressful in a sample of 10 workers?

f. What is the standard deviation of the number who find their jobs stressful in a sample of 10 workers?