Complete Probability Distributions

Bob is taking a 100 question test.  They have a 90 % probability of getting any one question correct.  WHICH IS THE CORRECT FORMULA TO FIND OUT THE PROBABILITY that they will answer EXACTLY 70  questions correctly?

• ₁₀₀C₇₀   ( 0.18  )³⁰ ( 0.90  )⁷⁰
  

• ₁₀₀C₇₀   ( 0.10  )³⁰ ( 0.90  )⁶⁰

• ₁₀₀C₇₀   ( 0.10  )³⁰ ( 0.90  )⁷⁰

• ₉₉C₇₀   ( 0.10  )³⁰ ( 0.90  )⁷⁰

Suppose that a quiz consists of 20 True-False questions. A student hasn't studied for the exam and will just randomly guesses at all answers (with True and False equally likely). How would you find the probability that the will student get 8 or fewer answers correct? √

• Find the probability that X=8 in a binomial distribution with n = 20 and p=0.5. 

• Find the area between 0 and 8 in a uniform distribution that goes from 0 to 20. 

• Find the probability that X=8 for a normal distribution with mean of 10 and standard deviation of √5

• Find the cumulative probability for 8 in a binomial distribution with n = 20 and p = 0.5. 

At a certain intersection, the light for eastbound traffic is red for 15 seconds, yellow for 5 seconds, and green for 30 seconds.  Find the probability that out of the next eight eastbound cars that arrive randomly at the light,exactly three will be stopped by a red light.

• 0.254

• 0.147

• 0.027

• 0.1940

The following table represents the probability distribution X, the employment status of adults in a city. What is the probability that the adults isn't retired?

• Yes, because all of the probabilities are between 0 and 1 inclusive and the sum of all the probabilities is 1.
• No, all probabilities are not be between 0 and 1 inclusive
• No, the sum of all the probabilities is not 1.
• Yes, because the distribution is symmetric

The following table represents the probability distribution X, the employment status of adults in a city. What is the probability that the adults isn't retired?

If you want to know how many trials you will need before your first success, use the ????? model.

• Geometric

• Binomial

• Normal

• Calculator

If you want a certain number of successes in a set amount of trials, use the ????? model.

• geometric

• binomial

• normal

• calculato

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? (Hint: It may help to use the complement.)

• 0.088

• 0.697

• 0.214

• 0.303

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

• (100C25)(1/6)²⁵(5/6)⁷⁵

• (100C25)(1/6)²⁵(5/6)¹⁰⁰

• (100C4)(1/4)²⁵(3/4)⁷⁵

• (100C4)(1/6)²⁵(5/6)⁷⁵