# A math quiz

SHORT ANSWER. Write the best answer. Show work separately.

Find the probability.

1) A packet of sour worms contains four strawberry, four lime, two black currant, two orange

sour, and three green apples worms. What is the probability that Dylan will not choose a

green apple sour worm, P(not green apple)?

2) Two 6-sided dice are rolled. What is the probability that the sum of the two numbers on

the dice will be greater than 9?

List the outcomes of the sample space.

3) A box contains 10 red cards numbered 1 through 10. List the sample space of picking one

card from the box.

Find the odds.

4) The probability of a person getting a job interview is 0.54. What are the odds against

getting the interview?

4)

Find the indicated probability.

5) In a family with family with 4 children, excluding multiple births, what is the probability

of having 2 girls and 2 boys, in that order? Assume that a boy is as likely as a girl at each

birth.

Find the probability.

6) Samantha is taking courses in math and English. The probability of passing math is

estimated at 0.4 and English at 0.6. She also estimates that the probability of passing at least

one of them is 0.8. What is her probability of passing both courses?

Solve the problem.

7) A drug company is running trials on a new test for anabolic steroids. The company uses

the test on 400 athletes know to be suing steroids and 200 athletes known not to be using

steroids. Of those using steroids, the new test is positive for 390 and negative for 10. Of

those not using steroids, the test is positive for 10 and negative for 190. What is the

estimated probability of a false negative result (the probability that an athlete using

steroids will test negative)?

Find the probability.

8) A class of 40 students has 10 honor students and 13 athletes. Three of the honor students

are also athletes. One student is chosen at random. Find the probability that this student is

an athlete if it is known that the student is not an honor student.

Find the expected value.

9) A new light bulb has been found to have a 0.02 probability of being defective. A shop

owner receives 500 bulbs of this kind. How many of these bulbs are expected to be

defective?

Prepare a probability distribution for the experiment. Let x represent the random variable, and let P represent the

probability.

10) Two marbles are drawn from a bag in which there are 4 red marble and 2 blue marble. The

number of blue marbles is counted.

Find the probability.

11) If 80% of scheduled flights actually take place and cancellations are independent events,

what is the probability that 3 separate flights will all take place?

Provide an appropriate response.

12) The probability distribution for the random variable X is:

xi -1 0 1 2

pi 0.22 0.23 0.26 0.29

What is the expected value of X?

Find the probability.

13) The table lists the eight possible blood types. Also given is the percent of the U.S.

population having that type.

Type/RH factor Percent

O positive 38%

A positive 34%

B Positive 9%

O Negative 7%

A Negative 6%

AB Positive 3%

B Negative 2%

AB Negative 1%

Let E be the event that a randomly selected person in the U. S. has type B blood. Let F be

the event that a randomly selected person in the U. S. has RH-positive blood.

Find P(E|F).

Use a tree diagram to find the indicated probability. Draw the tree diagram on a separate sheet.

14) 3.9% of a secluded island tribe are infected with a certain disease. There is a test for the

disease, however the test is not completely accurate. 92% of those who have the disease

will test positive. However 4.4% of those who do not have the disease will also test

positive (false positives). What is the probability that any given person will test positive?

Round your answer to three decimal places if necessary.

Find the probability.

15) People were given three choices of soft drinks and asked to choose one favorite. The

following table shows the results.

diet cola root beer lemon drop

under 18 years of age 40 25 20

between 18 and 40 35 20 30

over 40 years of age 20 30 35

P(person is over 40