Probability Distributions

Which one of the following is a discrete random variable?

• Sam's height

• Sam weight

• Time Sam's runs the 110 m hurdles

• Amount of Sam's brothers and sisters

Classify: How many miles it takes to use up a tank of gas.

• Discrete

• Continuous

Is this a probability distribution?

• No, the sum of p(x) does not equal 1.

• Yes, all p(x) are between 0 and 1.

• No, all p(x) are not between 0 and 1.

• Yes, the sum p(x) is 1.

The table above shows a television station's advertisement sales. The distribution of sales for one 24-hour day is given. Solve for the mean. Round to the nearest hundredth.

• 31.8

• 15.68

• 0.20

• 1.00

The table above shows a television station's advertisement sales. The distribution of sales for one 24-hour day is given. Solve for the standard deviation. Round to the nearest hundredth.

• 35.76

• 268.1

• 16.3

• 1279.35

An algebra 2 test has 6 multiple choice questions with four choices with one correct answer each. If we just randomly guess on each of the 6 questions, what is the probability that you get exactly 3 questions correct? (You need to figure out the p value first. It is not given to you.)

• 96.2%
• 13.2%
• 8.31%
• 25.0

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 at least 2 of the first 10 blood donors has Type B blood? 

• 0.088
• 0.697
• 0.214
• 0.303 

Find the mean of a binomial distribution with n=50 and p=0.4

• 50

• 4

• 20

• 10

Find the standard deviation of a binomial distribution with n=50 and p=0.4 (Round to the nearest tenth)

• 4.2

• 3.5

• 12.0

• 6.2

When rolling two dice, the probability of rolling doubles is ⅙. Suppose that a game player rolls the dice five times, hoping to roll doubles. What is the probability the player gets doubles less than three times in 5 attempts?

• 0.161
• 0.965
• 0.015
• 0.997