… a recent scientific study has shown that those that have the most birthdays tend to live the longest.
(but those with fewer birthdays tend to be healthier and fitter)
Of course it makes sense, but it also highlights the need to be careful, very careful, with statistical information.
As a maths teacher, I am always being asked “What’s the point of this?” “When will I ever use this in real life?” etc. I can usually always find a practical example of where the maths we are studying is used in the world outside the classroom. (Although I do always ponder what answers Geography teachers give to similar questions. Why do we need to know how an Oxbow lake is formed? 🙂 )
The teaching, understanding and application of Handling Data (that’s statistics to those of us of ‘an age’) has never been more important than it is now. We live in the age of data. How do Facebook, Google et-al make their money? By gathering and selling on data.
We all owe it to ourselves to understand the data that is presented to us, whether that be by the media, politicians, advertisers, lawyers … the list is endless. And they will spin that data to their own advantage, so we need to be able to interpret and understand that data for ourselves and draw our own conclusions, not necessarily the conclusion they want us to reach.
Here’s a really simple example. When someone talks of ‘the average’ what do they mean? Probably just that – the mean, but the mode (the most common number) and the median (the middle number) are also technically ‘averages’ so it may just suit someone to talk about the average, but use the mode, rather than the mean, for their advantage.
Lets say a class of children did a test, marked out of twenty. These were the marks of the 5 pupils (it wasn’t a big class!)
8, 8, 9, 16, 19
So what’s the average mark? Well, traditionally, the ‘average’ is taken to mean the mean, so lets calculate the mean:
8 + 8 + 9 + 16 + 19 = 60 60 ÷ 5 (as 5 pupils did the test) = 12
So the average is 12 and 3 children would have to go home and tell mum and dad that they scored below average.
But being mathematically astute, they know that the median and mode are also averages.
In this case, the median is 9 (middle number) and the mode is 8 (the score that appears most often). For the pupils, in the case, the mode is the best average for them to quote: two children can go home saying they scored the average mark and the other 3 can all claim to be above average.
This is a simple, somewhat tongue in cheek example, but it neatly highlights how data can be presented in different ways to suit different purposes. You have been warned!
If you’d like to (or your child to!) practise calculating the mean, mode and median of a set of numbers, you can find a mean mode median and range worksheet at my Worksheets page. At the time of writing, this page is still under development, but I have made a useful mean mode median and range worksheet that is good to go – you can go directly to it by clicking here.