Statistics​
Causality

Statistics

Univariate statistics

• Measures of middle (mean, median mode)
• Measures of spread (range and interquartile range)
• Measures of spread (standard deviation)
• Histograms
• Box plots​

Bivariate statistics

• Association between variables
• The effect of outliers on correlation
• Causality
• Interpreting Pearson's correlation coefficient
• Interpolation and extrapolation​​

Correlation between two variables does not mean that a change in one variable causes a change in the other. For example:

• If a strong correlation between the number of cat owners and number of burglaries in towns is found, it does not mean that owning a cat increased or decreased the number of burglaries. We would describe this correlation as either being coincidental, or a third variable may be the cause. In this case the third variable may be the population of the town.

If a change in a variable does cause a change in the other variable, then we say a causal relationship occurs between them.