Binomial Distribution

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

If you were to flip a coin 20 times, what is the probability you would get at most 13 heads?

• .9423

• .1316

• .0577

• .0739

Suppose 39% of Americans will vote for Donald Trump on election day. If a random sample of 8 voters are selected, what is the probability that 6 or more will vote for Trump?

• .9635

• .0365

• .9561

• .0439

In Vietnam, the probability of rain is 70%.  Find the probability of it raining at most 2 days in a week.

• .9712

• .0250

• .0287

• .2988

In Vietnam, the probability of rain is 70%.  Find the probability of it raining at most 5 days in a week.

• .9712

• .6705

• .3294

• .5520

A research team at Cornell University conducted a study showing that approximately 10% of all businessmen who wear ties wear them so tightly that they actually reduce blood flow to brain, diminishing cerebral functions. At a board meeting of 20 businessmen, all of whom wear ties, what is the probability that at least one tie is too tight?

• 27.0%

• 12.2%

• 73.0%

• 87.8%

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

A test has 8 multiple choice questions with four choices with one correct answer each. If we just randomly guess on each of the 8 questions, what is the probability that you get at least 3 questions correct?

• 0.886

• 0.332

• 0.678

• 0.208

X ~ B(20, 0.5)

Find P(X = 7)

• 0.07

• 0.13

• 0.87

• 0.94

X ~ B(20, 0.5)

Find P(X ≤ 7)

• 0.07

• 0.13

• 0.87

• 0.94