There are 3 ways to find the average of a set of data – mean, median, and mode.

The **mean** can be found by adding up all the numbers in the set, then dividing the sum by the number of data in the set.

The **median** can be found by rearranging the figures in ascending or descending order, then choosing the middle value. If the total number of data is even, the median is the mean of the two middle values.

The **mode** is simply the number that occurs the most frequently in the set.

So which method should we use?

We should not use mode here because we are not trying to find the most popular value. It will not help us decide which plan he should sign up for. Instead, we can use both mean and median to help us derive the most accurate value.

mean**median**modeMean | = | (2.4 + 1.7 + 2.8 + 2.5 + 2.3 + 4.9 + 1.9 + 2.1 + 5.5 + 2.9 + 2.2 + 2.0)12 |

| ≈ | 2.77 |

To find the median, we first rearrange the values in ascending/descending order.

That would give us

The middle values are 2.3 and 2.4.

Thus, the median of this set of values is

= 2.3 + 2.42

= 2.35

Looking at the mean and median values, which are both lower than 3 GB, the businessman should choose Plan B.

However, we may need to look at the entire distribution of the data values to decide more accurately which plan to choose. In this case, he should only go ahead with Plan B if the majority of the values are lower than 3 GB.

Besides mobile data, you can also use these methods to find out your monthly expenditure! Can you think of more uses for them?