Random Variables 2020

A fair coin is flipped three times. What is the probability of seeing heads exactly once?

• 3/8

• 1/8

• 1/2

• 1/6

Tags

CCSS.HSS.CP.B.9

Integration: Consider the dot plot shown. A trial consists of selecting a single student at random from this sample. Let "x" = the number of candy bars this student sold.

Find P(x>2) :

• 4/5

• 3/5

• 2/5

• 2/15

Tags

CCSS.6.SP.B.4

CCSS.HSS.ID.A.1

A magazine has 1,620,000 subscribers, of whom 640,000 are women and 980,000 are men. Thirty percent of the women read the advertisements in the magazine and 50 percent of the men read the advertisements in the magazine. A random sample of 100 subscribers is selected. What is the expected number of subscribers in the sample who read the advertisements?

• 30

• 40

• 42

• 50

• 80

A nonprofit organization plans to hold a raffle to raise funds for its operations. A total of 1,000 raffle tickets will be sold $1.00 each. After all the tickets are sold, one ticket will be selected at random and it owner will receive $50.00. The expected value for the net gain for each ticket is -$0.95. What is the meaning of the expected value in this context?

• The ticket owners lose an average of $0.05 per raffle ticket.

• The ticket owners lose an average of $0.95 per raffle ticket.

• Each ticket owner will lost $0.95 per raffle ticket.

• A ticket owner would have to purchase 19 more tickets for the expected value of his or her net gain to increase to $0.00.

• A ticket owner has a 95% chance of having a ticket that is not selected.

Tags

CCSS.HSS.MD.B.5A

The following table shows the probability distribution for the number of books a student typically buys at the annual book fair held at an elementary school.

Let the random variable B represent the number of books a student buys at the next book fair. What is the expected value of B?

• 0

• 1.00

• 1.79

• 3.50

• 28

Tags

CCSS.HSS.MD.A.2

The quality control manager at a factory records the number or equipment breakdowns each day. Let the random variable Y represent the number of breakdowns in one day. The standard deviation of Y is 0.28. Which of the following is the best interpretation of the standard deviation?

• The number of breakdowns on a randomly selected day is expected to be 0.28.

• The number of breakdowns on a randomly selected day will by 0.28 away from the mean.

• The average number of breakdowns per day for a random sample of days is expected to be 0.28

• On average, the number of breakdowns per day varies from the mean by about 0.28.

• The number of breakdowns per day for a random sample of days is expected to be 0.28 away from the mean.

Which of the following is NOT an assumption of the Binomial distribution?

• All trials must be independent.
• Each trial must be classified as a success or a failure.
• All trials are dependent on each other.
• The number of successes in the trials is counted.

Tags

CCSS.HSS.CP.A.2

CCSS.HSS.CP.A.3

Is the distribution below a probability distribution? Why or why not?

• Yes. All P(x) values are between 0 and 1, and ∑P(x) = 1
• No, not all P(x) values are between 0 and 1.
• No, ∑P(x) ≠ 1.

Tags

CCSS.HSS.MD.A.3

CCSS.HSS.MD.A.1

CCSS.HSS.MD.A.4

An algebra 2 test has 6 multiple choice questions with four choices with one correct answer each. If we just randomly guess on each of the 6 questions, what is the probability that you get exactly 3 questions correct?

• 0.962

• 0.132

• 0.831

• 0.250

Tags

CCSS.HSS.CP.B.9

The American Red Cross says that about 11% of the U.S. population has Type B blood. A blood drive is being held at your school. What is the probability that at least 2 of the first 10 blood donors has Type B blood? 

• 0.088
• 0.697
• 0.214
• 0.303 

Tags

CCSS.HSF-LE.A.1C