Mean Standard Deviation Binomial Distribution

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.

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.

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

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 

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

Find the mean of a binomial distribution with n=50 and p=0.4

• 50

• 4

• 20

• 10

Find the standard deviation of a binomial distribution with n=50 and p=0.4 (Round to the nearest tenth)

• 4.2

• 3.5

• 12.0

• 6.2

A test consists of 800 true or false questions. If the student guesses on each question, what is the standard deviation of the number of correct answers?

• 20

• 2

• 0

• 14.14

In a recent survey, 80% of the community favored building a police substation in their neighborhood. If 15 citizens are chosen, what is the standard deviation of the number favoring the substation?

• 1.55

• 2.40

• 0.98

• 0.55

Fifty-seven percent of families say that their children have an influence on their vacation plans. Consider a sample of eight families who are asked if their children influence their vacation plans. Find the probability of exactly 5 families who said yes that their children have an influence on their vacation plans.

• 0.126

• 0.268

• 0.765

• 0.011