Binomial Probability or No

A survey found that 25% of pet owners had their pets bathed professionally rather than do it themselves. If 18 pet owners are randomly selected, find the probability that exactly 5 people have their pets bathed professionally.

• 3.42

• 1.03

• 0.072

• 0.199

Which descriptions are true for a binomial distribution? Select all that apply.

• The probability of success must be the same for each event.

• The probability for each event must be 0.5.

• There can be only two possible outcomes - success and failure.

• The probabilities must add to 1.

• Each trial must be independent.

Barry Bonds has a career batting average of .298. What is the probability that he will get 6 hits in his next 10 at-bats?

• 3.58%

• 5.46%

• 22.67%

• 100%

If you were to flip a coin 20 times, what is the probability you would get exactly 10 heads?

• 50%

• 17.62%

• 58.81%

• 41.19%

The American College of Obstetricians and Gynecologists reports that 32% of all births in the United States take place by Caesarian section each year. Five woman are about to give birth.

What is the binomial probability that less than 3 will have a C-section birth?

• 0.0391

• 0.1906

• 0.9609

• 0.8095

Answer explanation

Binomial Probability Formula!

n = 5

p = 0.32

q = 1 - p = 0.68

x is "less than 3", so you have to find the probability when x is 2, 1 and 0. Then add them together.

p(0) = 0.1454

p(1) = 0.3421

p(2)=0.322

So, 0.1454 + 0.3421 + 0.322 = 0.8095

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

Sara takes a test that has 6 multiple choice questions, where each question has four possible choices. If she randomly guesses on each question, what is the probability that she will get exactly 3 questions correct?

• 0.962

• 0.831

• 0.132

• 0.250

When rolling a fair die 100 times, what is the probability of rolling a "4" exactly 25 times?

• 1.0%

• 16.7%

• 25%

• 2.1%

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 

When rolling two dice, the probability of rolling doubles is ⅙. Suppose that a game player rolls the dice four times, hoping to roll doubles. Find the probability that the player gets doubles twice in 4 attempts.

• 88.4%

• 11.6%

• 98.4%

• 1.6%