AP Statistics FINAL ch. 6

Which of the following random variables should be considered continuous?

The time it takes for a randomly chosen woman to run 100 meters

Use scenario 6-6. The probability that X is between 0.5 and 1.5 is

1/2

Use scenario 6-6. The probability that X = 1.5 is

0

6-5: A small store keeps track of the number X of customers that make a purchase during the first hour that the store is open each day. Based on the records, X has the following probability distribution.

The mean number of customers that make a purchase during the first hour that the store is open is

3.0

6-5: A small store keeps track of the number X of customers that make a purchase during the first hour that the store is open each day. Based on the records, X has the following probability distribution.

The std dev. of the number of customers that make a purchase during the first hour that the store is open is

1.4

I roll a pair of fair dice and let X = the sum of the spots on the two sides facing up. The probability that X is 2, 11, or 12 is

4/36

6-12: There are twenty multiple-choice questions on an exam, each having responses a, b, c, or d. Each question is worth 5 points and only one option per question is correct. Suppose the student GUESSES the answer to each question, and the guesses from question to question are independent.

Which of the following expresses the probability that the student gets no questions correct?

(0.75)^20

A small class has 10 students. Five of the students are male and five are female. I write the name of each student on a 3-by-5 card. The cards are shuffled thoroughly and i draw cards, one at a time, until I get a card with the name of a male student. Let X be the number of cards I draw. The random variable X has which of the following probability distributions?

None of the above

6-15: Suppose that 40% of the cars in a certain town are white. A person stands at an intersection waiting for a white car. Let X = the number of cars that must drive by until a white one drives by.

Use scenario 6-15. P(X<5)=

0.8704

For which of the following counts would a binomial probability model be reasonable?

The number of 7's in a randomly selected set of five random digits from a table of random digits.