ICAS Statistics and Probability

Question 1

What is the mean of 4, 6, 8, 10 and 12?

Accepted Answer

8

Answer

The mean is the total divided by how many numbers there are. 4 + 6 + 8 + 10 + 12 = 40, and 40 ÷ 5 = 8.

Question 2

A fair six-sided die is rolled once. What is the probability of rolling an even number?

Accepted Answer

1/2

Answer

The even numbers are 2, 4 and 6. That is 3 of the 6 equally likely outcomes, so the probability is 3/6 = 1/2.

Question 3

What is the median of 3, 9, 1, 7, 5?

Accepted Answer

5

Answer

In order, the numbers are 1, 3, 5, 7, 9. The middle value, the median, is 5.

Question 4

What is the mode of 2, 4, 4, 5, 7, 7, 7, 9?

Accepted Answer

7

Answer

The mode is the value that appears most often. 7 appears three times, more than any other number.

Question 5

A bag holds 3 red, 5 blue and 2 green marbles. One marble is picked without looking. What is the probability it is blue?

Accepted Answer

1/2

Answer

There are 3 + 5 + 2 = 10 marbles and 5 are blue. 5/10 = 1/2.

(ICAS) ICAS Practice Test