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Bar charts
Used when data is clearly divided up into categories – this is known as DISCRETE data.
Scattergrams / scatter graphs
Don’t show us differences, they show us associations / relationships or CORRELATIONS.
Histograms
The bars touch, this is to show that the data is CONTINUOUS.
Line graphs
Represent continuous data and used to show how something changes in value depending on something.
What is a normal distribution?
A normal distribution is an arrangement of data that is symmetrical and forms a bell-shaped pattern.
The top / centre of the graph = the mean, medium and mode!
Skewed distributions
Negative skew (tail to the left)
Could be the result of a very easy test, most participants scored very highly which leaves a tail of anomalous low scorers.
The mean is pulled to the eft by the lower scores being the minority but the mode is still the highest point.
Positive skew (tail to the right)
Could be the result of a very hard test, most participants scored low marks which leaves a tail of ambiguous high scorers.
The mean is pulled to the right by the higher scores being the minority but the mode is still the highest point.
