1) Find the mean of the given probability distribution.

2) The random variable x is the number of houses sold by a realtor in a single month at the Sendsom's Real Estate office. Its probability distribution is as follows.

3)
Find the standard deviation for the given probability distribution.

4) In a certain town, 70% of adults have a college degree. The accompanying table describes the probability distribution for the number of adults (among 4 randomly selected adults) who have a college degree. Find the standard deviation for the probability distribution.

5) In a game, you have a  probability of winning  and a  probability of losing  What is your expected value?

6) A contractor is considering a sale that promises a profit of $26,000 with a probability of 0.7 or a loss (due to bad weather, strikes, and such) of $8000 with a probability of 0.3. What is the expected profit?

7) A test consists of 10 true/false questions. To pass the test a student must answer at least 6 questions correctly. If a student guesses on each question, what is the probability that the student will pass the test?

8) A machine has 11 identical components which function independently. The probability that a component will fail is 0.2. The machine will stop working if more than three components fail. Find the probability that the machine will be working.

9) In a certain college, 33% of the physics majors belong to ethnic minorities. If 10 students are selected at random from the physics majors, that is the probability that no more than 6 belong to an ethnic minority?

10) Find the probability of at least 2 girls in 6 births. Assume that male and female births are equally likely and that the births are independent events.

x | P(x) 0 0.26 10.11 2 0.16 3 0.05 4 0.42