Everything Maths Grade 10

The mean is sometimes also called the average or the arithmetic mean.

Worked example 3: Calculating the mean

QUESTION

What is the mean of the data setf10; 20; 30; 40; 50g?

SOLUTION

Step 1: Calculate the sum of the data

10 + 20 + 30 + 40 + 50 = 150

Step 2: Divide by the number of values in the data set to get the mean

Since there are 5 values in the data set, the mean is:

mean=

150

5

= 30

Median EMA72

DEFINITION: Median

The median of a data set is the value in the central position, when the data set has been arranged from the

lowest to the highest value.

Note that exactly half of the values from the data set are less than the median and the other half are greater
than the median.

To calculate the median of a quantitative data set, first sort the data from the smallest to the largest value and
then find the value in the middle. If there is an odd number of values in the data set, the median will be equal
to one of the values in the data set. If there is an even number of values in the data set, the median will lie
halfway between two values in the data set.

Worked example 4: Median for an odd number of values

QUESTION

What is the median off10; 14; 86; 2; 68; 99; 1g?

SOLUTION

Step 1: Sort the values

The values in the data set, arranged from the smallest to the largest, are

1; 2; 10; 14; 68; 86; 99

Chapter 10. Statistics 359