Averages and Range

Range = highest amount - lowest amount Range

Sometimes we are told that the average family has 2.4 children. Types of average There are three types of average: mode, median and mean

Mean If amounts are shared out equally, then each person (or item) will get the same amount which is the mean. If the total number of children are shared out between all the families then there are 2.4 children per family Median When the amounts are arranged in order the middle one is the median. Mode The mode is the most common amount. Most families have 2 children so the mode of the number of children is 2.

Frequency is the number of times an item appears or event happens The table shows the frequency of ice cream sold per hour: Ice creamTally per hourFrequency ChocolateIIIIII6 VanillaIII3 StrawberryIIIII5 Mint choc chipIIIIIII7 Rocky roadII2 Frequency

A dice is tossed 15 times and the scores were: 6, 5, 4, 3, 4, 1, 1, 2, 4, 4, 3, 2, 3, 5, 4 Score Frequency From the table we can see that the score with the highest frequency is 4, so the mode is 4. Frequency

Writing the scores in order gives 1, 1, 2, 2, 3, 3, 3, 4, 4, 4, 4, 4, 5, 5, 6 The median is the middle one i.e. 4 The mean is found by adding together all the scores and dividing by the number of scores (15) = 51 Median and Mean

The mean height of this mountain range is 1000m 1000 m

The mean height of this mountain range is also 1000m. The mean can mask extreme values m

Mean and Mode and Frequency Distributions The ages of 50 people in a maths club are given below Find the mean and mode of their ages. 23 has the highest frequency, so the mode is 23 Age Frequency

To find the mean rewrite the frequency table as shown Age (A) Frequency (f) Frequency × Age (fx A) total