12. Assume random variablexfollows a probability distribution shown in the table below:

x P(x)

0 0.15

1 0.2

2 0.05

3 0.6

Find the mean of this probability distribution._____Round your answer to one decimal place.

Find the standard deviation of this probability distribution. _____Round your answer to two decimal places.

13. Brendan buys a bag of cookies that contains 4 chocolate chip cookies, 7 peanut butter cookies, 5 sugar cookies and 4 oatmeal raisin cookies. What is the probability that Brendan randomly selects a peanut butter cookie from the bag, eats it, then randomly selects another peanut butter cookie?

Express your answer as a reduced fraction. _____

16. A college softball player, on average, has a 0.158 probability of hitting the ball in a single "at bat." In one game, she gets 7 "at bats."

Fill in the appropriate values (use three decimal places, where appropriate):

n (number of trials) =____

p (probability of successes) = _____

q (probability of failures) =_____

What is the probability she will get at least 3 hits in the game? (Please round answer to three decimal places).

17. Out of 400 people sampled, 80 owned a pet. Based on this, construct a 99% confidence interval for the true population proportion of people who own pets.

Give your answers as decimals, to three places.

_____< p <_____