I don't like percentage plots. If one thing goes up by 1 point, then the rest must necessarily go down by 1 point (distributed between them). I think that's a bit confusing. I'd much prefer absolute values.
4 small groups of students (pairs or triples) repeated enough times to cover whole class. Each group gets one of these three charts or the table. Plenary at end: the ones who got the % bar chart often have totally different sentences from the other three groups.
I tend to give the % bar chart to the more confident students.
Yes, but human being seem to struggle with the concept, regularly assuming that a decreasing percentage necessarily implies a decreasing absolute number as well.
If they aim is to communicate a true representation of reality then you need to take that into account.
Consider that (unless the absolute value varies by more than an order of magnitude) you can see relative values very easily on an absolute graph, but you can never see absolute values on a percentage graph. It would be interesting to know, for example if the loser is still growing due to getting a smaller portion of an increasing market.
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I don't like percentage plots. If one thing goes up by 1 point, then the rest must necessarily go down by 1 point (distributed between them). I think that's a bit confusing. I'd much prefer absolute values.
[PDF] http://sohcahtoa.org.uk/pages/files/fredas-tea-stall-three-c...
4 small groups of students (pairs or triples) repeated enough times to cover whole class. Each group gets one of these three charts or the table. Plenary at end: the ones who got the % bar chart often have totally different sentences from the other three groups.
I tend to give the % bar chart to the more confident students.
Personally, show me the numbers. Wins every time.
Isn't that exactly how it's supposed to work?
Yes, but human being seem to struggle with the concept, regularly assuming that a decreasing percentage necessarily implies a decreasing absolute number as well.
If they aim is to communicate a true representation of reality then you need to take that into account.
Consider that (unless the absolute value varies by more than an order of magnitude) you can see relative values very easily on an absolute graph, but you can never see absolute values on a percentage graph. It would be interesting to know, for example if the loser is still growing due to getting a smaller portion of an increasing market.
There are situations like survey research where percentages matter a lot and absolute values not so much.