NBT Statistics and Probability

Question 1

What is the mean of the following data set: 12, 15, 18, 22, 28?

Accepted Answer

19

Answer

The mean is the sum divided by the count: (12 + 15 + 18 + 22 + 28) ÷ 5 = 95 ÷ 5 = 19. The mean represents the average value.

Question 2

A fair die is rolled once. What is the probability of getting a number greater than 4?

Accepted Answer

1/3

Answer

Numbers greater than 4 on a die are 5 and 6 — that's 2 favourable outcomes out of 6 possible. P = 2/6 = 1/3.

Question 3

What is the median of: 3, 7, 9, 12, 15, 18, 21?

Accepted Answer

12

Answer

With 7 values in order, the median is the 4th value (middle). The median is 12. For an odd number of data points, the median is the exact middle value.

Question 4

If P(A) = 0.4 and P(B) = 0.3, and A and B are independent events, what is P(A and B)?

Accepted Answer

0.12

Answer

For independent events, P(A and B) = P(A) × P(B) = 0.4 × 0.3 = 0.12. Independence means one event does not affect the probability of the other.

Question 5

The mode of a data set is:

Accepted Answer

The most frequently occurring value

Answer

The mode is the value that appears most frequently in a data set. A data set can have no mode, one mode (unimodal), or multiple modes (bimodal or multimodal).

(NBT) National Benchmark Test Practice Test

(NBT) National Benchmark Test Practice Test

NBT Statistics and Probability