Gaokao Exam Mathematics: Probability and Statistics 2

Question 1

In a normal distribution, approximately what percentage of data falls within one standard deviation of the mean?

Accepted Answer

68%

Answer

50%

Answer

95%

Answer

99.7%

Question 2

A box contains 4 white and 6 black marbles. Two marbles are drawn without replacement. What is the probability both are white?

Accepted Answer

2/15

Answer

4/25

Answer

1/5

Answer

4/15

Question 3

Which of the following correctly describes the variance of a dataset?

Accepted Answer

The average of squared deviations from the mean

Answer

The average of all data values

Answer

The square root of the standard deviation

Answer

The difference between the maximum and minimum values

Question 4

If a random variable X follows a binomial distribution with n = 10 and p = 0.5, what is E(X)?

Accepted Answer

5

Answer

2.5

Answer

7.5

Answer

10

Question 5

A frequency table shows scores: 60 (5 students), 70 (8 students), 80 (7 students), 90 (5 students). What is the mode?

Accepted Answer

70

Answer

60

Answer

80

Answer

90

Question 6

Two independent events A and B have P(A) = 0.5 and P(B) = 0.6. What is P(A ∩ B)?

Accepted Answer

0.30

Answer

0.10

Answer

0.55

Answer

1.10