GRE Probability and Statistics Concepts 2

Question 1

A fair six-sided die is rolled twice. What is the probability that the sum of the two rolls equals 7?

Accepted Answer

1/6

Answer

1/9

Answer

1/12

Answer

5/36

Question 2

If events A and B are independent with P(A) = 0.4 and P(B) = 0.5, what is P(A and B)?

Accepted Answer

0.2

Answer

0.9

Answer

0.1

Answer

0.45

Question 3

The mean of the data set {4, 8, 8, 10, 15} is closest to which value?

Accepted Answer

9

Answer

8

Answer

10

Answer

11

Question 4

A bag has 3 red and 2 blue marbles. Two are drawn without replacement. What is the probability both are red?

Accepted Answer

3/10

Answer

9/25

Answer

2/5

Answer

1/5

Question 5

What is the median of the set {12, 3, 7, 9, 15, 6}?

Accepted Answer

8

Answer

7

Answer

9

Answer

8.5

Question 6

In a standard normal distribution, approximately what percent of values fall within one standard deviation of the mean?

Accepted Answer

68%

Answer

50%

Answer

95%

Answer

99.7%

Question 7

If P(A) = 0.7, what is the probability that A does NOT occur?

Accepted Answer

0.3

Answer

0.7

Answer

0.0

Answer

1.0