Data distributions

What is a normal distribution?

Where most scores are on or around the mean with decreasing amounts away from the mean

What does normal distribution look like on a graph?

• The mean, median and mode all have the same midpoint

• Symmetrical, bell shaped curve when plotted on a graph

• Dispersion of scores either side of the midpoint is symmetrical

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What is a positively skewed distribution?

There are a few high extreme scores causing the mean to be higher than the median and mode

What does a positive skew look like on a graph?

The peak of the graph will be to the right

What is a negatively skewed distribution?

There are a few low extreme scores causing the mean to always be lower than the median and mode

What does a negative skew look like on a grpah?

The peak of the graph will be to the right