Random Variable and Probability Distribution, Mean and Variance

Find the missing value for P(X=5) in the probability ditribution:

• 0.11

• 0.21

• 0.01

• 0.31

Determine which of the following distribution is NOT a probability distribution.

• A

• B

• C

• D

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 represents the probability of guessing correct on a 5 question true-false quiz.  Find the probability for at least 4 questions correct.

• .03125

• .15625

• .3125

• .1875

What does P(Y<3) mean?

• The probability that the random variable Y is greater than 3.

• The probability that the random variable Y is less than 3.

• The probability that the random variable X is greater than 3.

• The probability that the random variable X is less than 3.

Find P( X = 4).

• 1.00

• 0.91

• 0.02

• 0.07

Consider the following distribution where X = number of mice caught in an apartment in a night:

Mice | Probability

0 | 0.12

1 | 0.20

2 | 0.31

3 | 0.14

4 | 0.16

5 | 0.07

Which of the following means "trapping at least one mouse?"

• X<1

• X<1

• X>1

• X>1

Consider the following distribution where X = number of mice caught in an apartment in a night:

Mice | Probability

0 | 0.12

1 | 0.20

2 | 0.31

3 | 0.14

4 | 0.16

5 | 0.07

Which of the following means "trapping less than 2 mice?"

• X<2

• X<3

• X>2

• X>2

Consider the following distribution where X = number of mice caught in an apartment in a night:

Mice | Probability

0 | 0.12

1 | 0.20

2 | 0.31

3 | 0.14

4 | 0.16

5 | 0.07

What is the probability of trapping at least three mice?

• 0.14

• 0.37

• 0.23

• 0.16

Consider the following distribution where X = number of mice caught in an apartment in a night:

Mice | Probability

0 | 0.12

1 | 0.20

2 | 0.31

3 | 0.14

4 | 0.16

5 | 0.07

What is the probability of trapping fewer than 3 mice?

• 0.14

• 0.37

• 0.63

• 0.16