Spiderman has recently experienced some faulty web shooters. Suppose he has 100 web shooters at home, 15 of which are faulty. He randomly samples 10 web shooters to test if they work.

a. What is the probability that exactly 4 of the selected web shooters are faulty.

b. What is the probability that at least 7 are defective?

c. What is the probability that between 3 and 5 inclusive are defective?

d. How many do you expect to be defective?

e. What is the standard deviation of the number of defective web shooters?