Statistics
Measures of spread (range and IQR)

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​​

We can gain a better understanding of a data set by locating the middle or centre of the data and measuring the spread. Knowing one of these without the other is often of little use.
The range is one way to gain an idea about how spread out a data set is. The range of a data set is the difference between the maximum data value and the minimum data value.