Mean, Mode, Median and Range
The mean is what most people call the "average" - you add up all your numbers and divide by how many you've got. With the numbers 9, 3, 8, 3, 6, 1, you'd calculate: 9 + 3 + 8 + 3 + 6 + 1 = 30, then divide by 6 numbers to get a mean of 5.
The mode is dead simple - it's just the number that appears most often in your data set. Looking at our example (9, 3, 8, 3, 6, 1), the number 3 pops up twice whilst everything else appears once, so 3 is your mode.
Finding the median requires a bit more work since you need to arrange your numbers from smallest to largest first. Our jumbled numbers 9, 3, 8, 3, 6, 1 become 1, 3, 3, 6, 8, 9 when ordered. With six numbers, the median sits between the 3rd and 4th values (3 and 6), giving us 4.5.
The range shows you how spread out your data is by finding the difference between your highest and lowest numbers. Take 9 (highest) minus 1 (lowest) and you get a range of 8.
Quick Tip: Remember "Mean is Mean-spirited" (lots of calculation), "Mode is Most common", "Median is Middle", and "Range is the gap between biggest and smallest!"