Random Variables and Distributions

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.

Find the mean (expected value) of the probability distribution.

• 85

• 83.2

• 87.1

• 84.4

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

Given the probability model in the table below, what is the expected value of the random variable?
  X        50          20        5
P(X)     0.1         0.3      0.6

• 14

• 4.67

• 5

• 7.5

• Yes, because all of the probabilities are between 0 and 1 inclusive and the sum of all the probabilities is 1.
• No, all probabilities are not be between 0 and 1 inclusive
• No, the sum of all the probabilities is not 1.
• Yes, because the distribution is symmetric

It is a variable whose values are determined by chance.

• Random Variable

• Discrete Variable

• Continuous Variable

• Independent Variable

What is the numerical quantity assigned to the outcome of an experiment usually denoted by an uppercase letter such as X?

• Frequency

• Probability

• Random variable

• Sample

Which of the following refers to a rule that assigns a numerical value or characteristic to an outcome of an experiment?

• Expected Value

• Random Variable

• Range Space

• Probability Distribution

• Yes, because all of the probabilities are between 0 and 1 inclusive and the sum of all the probabilities is 1.
• No, all probabilities are not be between 0 and 1 inclusive
• No, the sum of all the probabilities is not 1.
• Yes, because the distribution is symmetric

A random variable is defined by a rule that assigns a _______________ to every outcome in a sample space.

• number

• letter

• Event

• probability