STATS: Ch 5 Final Review

Let X = the score out of 10 points on a randomly selected test in a statistics class. The table gives the probability distribution of X.

• 0.04

• 0.08

• 0.88

• 0.92

Which of the following random variables are continuous?

I. D = the number of grains of sand on a randomly selected area of a large beach

II. A = the amount of ink remaining in a pen randomly selected from a desk

III. I = the number of steps taken in a day by a randomly selected high school student

• I, II, and III

• II and III

• I and III

• II only

Which of the following random variables are discrete?

I. D = the number of grains of sand on a randomly selected area of a large beach

II. A = the amount of ink remaining in a pen randomly selected from a desk

III. I = the number of steps taken in a day by a randomly selected high school student

• I, II, and III

• II and III

• I and III

• II only

Let X = the score out of 3 points on a randomly selected pop quiz in a statistics class. The table gives the probability distribution of X. Calculate and interpret the expected value of X.

• The average score will be about 2.26.

• If many, many tests are randomly selected, their average score will be about 2.26.

• If a test is randomly selected, the average score will be about 2.26.

• None of these is correct.

Let X = the score out of 3 points on a randomly selected pop quiz in a statistics class. The table gives the probability distribution of X. Calculate and interpret the expected value of X.

• The average score will be about 1.78.

• It a test is randomly selected, the average score will be about 1.78.

• If many, many tests are randomly selected, their average score will be about 1.78.

• None of these is correct.

Let X = the score out of 3 points on a randomly selected pop quiz in a statistics class. The table gives the probability distribution of X. Calculate and interpret the standard deviation of X.

• A randomly selected test score will typically differ from the mean by about 0.632 points.

• If a test is randomly selected, the average score will be about 0.795 points.

• A randomly selected test score will typically differ from the mean by about 0.795 points.

• None of these is correct

Let X = the score out of 3 points on a randomly selected pop quiz in a statistics class. The table gives the probability distribution of X. Calculate and interpret the standard deviation of X.

• If a test is randomly selected, the average score will be about 0.944 points

• A randomly selected test score will typically differ from the mean by about 0.944 points.

• A randomly selected test score will typically differ from the median by about 0.891 points.

• None of these is correct.

An online retailer claims the probability of one of their packages arriving on time is 0.99. Assume that delivery times for packages are independent of one another. What is the probability that in 12 randomly selected orders, exactly 10 are on time?

• 0.0062

• 0.9940

• 0.0060

• None of these are correct.

A bowler believes the probability that she bowls a strike is 0.8. Suppose she bowls 10 times. Let B = the number of strikes. The probability distribution of B is shown here. Find the probability that the bowler gets more than 8 strikes.

• 0.3222

• 0.6242

• 0.6778

• 0.3758

A bowler believes the probability that she bowls a strike is 0.8. Suppose she bowls 10 times. Let B = the number of strikes. The probability distribution of B is shown here.

Find the probability that the bowler gets fewer than 8 strikes.

• 0.3758

• 0.3222

• 0.6778

• 0.6242