NBT Statistics and Probability 2

Question 1

What is the range of the data set: 5, 8, 12, 3, 15, 7?

Accepted Answer

12

Answer

Range = maximum - minimum = 15 - 3 = 12. The range gives a simple measure of how spread out the data is.

Question 2

A bag contains 5 red balls and 3 blue balls. If one ball is drawn at random, what is the probability it is blue?

Accepted Answer

3/8

Answer

Total balls = 5 + 3 = 8. P(blue) = number of blue balls ÷ total = 3/8. Each ball has an equal chance of being drawn.

Question 3

The standard deviation measures:

Accepted Answer

The spread of data around the mean

Answer

Standard deviation measures how spread out data values are around the mean. A small standard deviation means data points cluster near the mean; a large one means they are more spread out.

Question 4

If a coin is tossed 3 times, what is the probability of getting exactly 2 heads?

Accepted Answer

3/8

Answer

The possible outcomes with exactly 2 heads are: HHT, HTH, THH — that's 3 outcomes out of 2³ = 8 total. P = 3/8.

Question 5

What is the interquartile range (IQR) if Q1 = 15 and Q3 = 35?

Accepted Answer

20

Answer

IQR = Q3 - Q1 = 35 - 15 = 20. The IQR measures the spread of the middle 50% of the data and is resistant to outliers.

(NBT) National Benchmark Test Practice Test

(NBT) National Benchmark Test Practice Test

NBT Statistics and Probability 2