Averages and Range Range highest amount lowest amount

Averages and Range

Range = highest amount - lowest amount

Types of average Sometimes we are told that the average family has 2. 4 children. There are three types of average: mode, median and mean

Mode The mode is the most common amount. Most families have 2 children so the mode of the number of children is 2. Median When the amounts are arranged in order the middle one is the median. 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

Frequency is the number of times an item appears or event happens The table shows the frequency of ice cream sold per hour: Ice cream Tally per hour Frequency Chocolate IIIIII 6 Vanilla III 3 Strawberry IIIII 5 Mint choc chip IIIIIII 7 Rocky road II 2

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 1 2 3 4 5 6 Frequency 2 2 3 5 2 1 From the table we can see that the score with the highest frequency is 4, so the mode is 4.

Median and Mean Writing the scores in order gives 1, 1, 2, 2, 3, 3, 3, 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) 1+1+2+2+3+3+3+4+4+4+5+5+6 = 51

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

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

Mean and Mode and Frequency Distributions The ages of 50 people in a maths club are given below Age 20 21 22 23 24 25 26 27 28 29 30 Frequency 3 5 4 8 3 6 7 4 Find the mean and mode of their ages. 23 has the highest frequency, so the mode is 23 4 4 2

To find the mean rewrite the frequency table as shown Age (A) 20 21 22 23 24 25 26 27 28 29 30 total Frequency (f) Frequency × Age (fx A) 3 5 4 8 3 6 7 4 4 4 2 60 105 88 184 50 1237 72 150 182 108 112 116 60