4.3 Binomial Distribution

A Statistics quiz has 6 multiple choice questions. Each question has four choices with one correct answer each. If you 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 exactly 2 of the first 20 blood donors have Type B blood?

• 0.316

• 0.282

• 0.001

• None of these

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

• 0.886

• 0.321

• 0.678

• 0.208

32 percent of beach goers end up with some form of sunburn on any given day. If 75 people show up at a beach, what is the expected number who will get sunburn?

• 45

• 24

• 16

• 53

A bag contains 15 red marbles, 5 yellow marbles, and 30 green marbles. A trial consists of picking 8 marbles from this bag with replacement. Find the probability that exactly three of these marbles are red.

• 0.254

• 0.147

• 0.027

• 0.1940

The owner of a small convenience store is trying to decide whether to discontinue selling magazines. He suspects that only 5% of the customers buy a magazine and thinks that he might be able to use the display space to sell something more profitable.

If this owner is correct, what is the probability that at least 5 of his first 50 customers buy magazines?

• 0.104

• 0.896

• 0.066

• 0.774

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

• 0.9423

• 0.1316

• 0.0577

• 0.0739

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

• 0.010

• 0.167

• 0.212

• 0.021