Probability with Random Variables

• 1.67

• 1.077

• 2.0

• 1.41

• 1.67

• 1.0775

• 1.581

• 1.414

• .22

• .64

• .36

• .78

The graph shows the probability distribution for the number of orders per week for a randomly selected week at an Etsy store. What is the expected number of orders and the standard deviations of the number of orders?

• 44.5, 2.449

• 44.5, 2.291

• 44.64, 1.694

• 44.64, 1.672

The model shown above shows the probability for rental units based on the number of rooms. What is the expected value and the standard deviation of the number of rooms in a rental unit?

• 5, 2.7386

• 5, 2.5820

• 4.355, 1.5647

• 4.355, 1.2996

• Yes, because all of the probabilities are between 0 and 1 inclusive and the probabilities add to 1.

• No, all probabilities are not between 0 and 1

• No, the probabilities do not add to 1.

• Yes, because the distribution is symmetric

Let the random variable X be the number of best friends each of a Grade 3 student. The probability distribution of X is shown on the left. What is the probability histogram of this distribution?

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Which of the following is NOT a requirement for the Binomial distribution?

• All trials must be independent.

• Events are binary (success or failure)

• All trials are dependent on each other.

• There is a set # of trials

An algebra 2 test has 6 multiple choice questions with a 25% probability of guessing correctly. If we just randomly guess on each of the 6 questions, how to find the probability that you get exactly 3 questions correct?

• binomcdf(6, 0.25, 3)

• binompdf(6, 0.25, 3)

• binomcdf(6, 0.25, 2)

• 1-binomcdf(6, 0.25, 3)

The Red Cross says that about 11% of the U.S. population has Type B blood. A blood drive is being held at your school. How can you find the probability that at least 2 of the first 10 blood donors has Type B blood?

• binomcdf(10, 0.11, 2)

• binomcdf (10, 0.11, 1)

• 1 - binomcdf(10, 0.11, 2)

• 1 - binomcdf(10, 0.11, 1)