## What you need to know

Things to remember:

• This most is the most common number
• You don’t need to order your numbers, you can just count them, ignoring ones that don’t appear often.

There are two key pieces of information we need to learn:

• Frequency is a fancy way of saying “how often something happens”
• Mode is a fancy way of saying “the most frequent thing”

Find the mode of the following set of data

3          4          6          5          2          1          5

We can find the mode in one of two ways:

Method 1: Order the numbers.

1          2          3          4          5          5          6

We can now easily see that 5 is the most frequent, so must be our mode.

Method 2: Frequency table

Hint: Remember, frequency is just how many times we see something.

Number                       Frequency

1                                    1

2                                    1

3                                    1

4                                    1

5                                    2

6                                    1

What would happen if we changed the 6 to a 3?

Find the mode of the following set of data

3          4          3          5          2          1          5

Number                       Frequency

1                                   1

2                                   1

3                                   2

4                                   1

5                                   2

Well, now, there are two numbers that appear the most, 2 and 5. Because of this, we say that there are two modes and that the data is “bimodal”. If there were three modes, it would be called “trimodal”.

Modes don’t just have to be concerned with numbers.

A student records the colour of cars that drive by, which was the modal car colour?

Car colour                   Frequency

Red                             12

Blue                             23

Black                           15

Yellow                          6

Green                          10

Looking at the frequencies, blue was the most common car colour, so is the mode.

## Example Questions

#### Question 1: Find the mode of the following set of data:5          8          1          2          9          2          0          1          3

Number                       Frequency

0                                  1

1                                  2

2                                  2

3                                  1

5                                  1

8                                  1

9                                  1

1 and 2 are the modes. This data is bimodal.