12. Assume random variable *x* follows 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 t**wo 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 < _____

#### Top Answer

Question 12 Mean = 0*0.15 + 1*0.2 + 2*0.05 + 3*0.6 = 2.1 Variance = 0 2 *0.15 + 1 2 *0.2 + 2 2 *0.05 + 3 2 *0.6 - 2.1 2 =... View the full answer

#### Sign up to view the full answer

#### Other Answers

12) Mean = 2.1 Standard deviation = 1.179 13) Probability that Brendan randomly selects a peanut... View the full answer

(1) Mean = Expected value = E(X) = 2.1 Standard deviation, σ = 1.18 (Rounded at two decimal places) (2) Probability... View the full answer