Stats Probability 4.1-4.4

Angela, Breanna, Christine, Debbie, and Esther are in a club and they need to pick two people to go to a meeting. They write each persons name on equally sized pieces of paper, put them in a hat, and mix the papers thoroughly. Find the probability model for this chance process and use it to determine the probability that Angela gets to go to the meeting.

• 9/25

• 2/5

• 16/25

• 3/5

A survey of all of the students at a school revealed that 30% of the students drove to school, 80% of the students have at least one sibling, and 24% of the students drove to school and have at least one sibling. Are the events driving to school and have at least on sibilant independent?

• Yes, because 0.24/0.56 does not equal 0.30

• Yes, because 0.24/0.80 equals 0.30.

• No, because 0.24/0.56 does not equal 0.30.

• No, because 0.24/.80 equals 0.30

When a fair die is rolled, the probability of any side landing face up is 1/6. Which of the following is the best interpretation of the probability?

• When you roll a die 6 times, exactly one time a five will land face up.

• If you roll a die 600 times, exactly one hundred times a five will land face up.

• As you roll the die over and over many times, the number of times a five lands face up out of the total number of rolls will get closer and closer to 1/6.

• If you rolled the die twice in a row and both times a five landed face up, the next time you roll you are less likely to roll a five because rolling a five should happen every six rolls

For the upcoming school fair, each ride requires from 0 to 3 tickets to ride. The probability distribution of the number of tickets needed for a randomly selected ride at the fair is shown to the side. What is the probability that at least one ticket is required for the ride?

• 0.1

• 0.2

• 0.3

• 0.9

At a local high school, 40% of students drink soda regularly, 30% drink coffee regularly, and 10% drink both regularly. If a student was randomly selected from this school, what is the probability that the student drinks soda if we know that the student drinks coffee regularly?

• 0.10

• 0.33

• 0.30

• 0.25

Three of the following statements contain incorrect myths about randomness. Which one of the following statements is true?

• A spinner with three equal sections will be spun thirty times. The spinner will land in each section ten times.

• A fair coin is flipped 5 times and lands heads up each time. The next flip is more likely to be a tail.

• When rolling a fair die 6 times, it is just as likely to get the sequence 123456 as it is to get 111111.

• A basketball player makes 80% of the shots she takes. She has made her last 10 shots so she is due to miss her next shot because of the law of averages.

For the upcoming school fair, each ride requires from 0 to 3 tickets to ride. The probability distribution of the number of tickets needed for a randomly selected ride at the fair is shown to the side. What is the probability that more than one ticket is required for the ride?

• 0.3

• 0.4

• 0.7

• 0.9

At a local restaurant, 40% of the lunch customers order a hamburger, 70% of the lunch customers order French fries, and 30% order both a hamburger and French fries. If a customer was randomly selected from this restaurant, what is the probability that the customer orders fries if we know they have ordered a hamburger.

• 0.30

• 0.40

• 0.43

• 0.75

A teacher at a local high school surveyed the senior students. Two of the variables recorded for the 200 students were whether the student had any sibilings and whether the student typically drives to school. The following table summarizes the responses. Let D be the event thet a student drives to school and S be the event that the student has at least on sibling. Find P(D given that you know S ).

• 80/130

• 80/120

• 80/200

• 130/200