Understanding Histograms

Mean

the average of the whole set

Median

the middle value in a data set when arranged in order

Mode

the value that appears most frequently in a data set

Use the mean

to describe the center when the data is symmetric and there are no outliers that could skew the average.

Use the median

to describe the center when the data set contains outliers or is skewed

Range

the difference between the highest and lowest values in a data set.

IQR

the difference between the first and third quartiles, measuring the spread of the middle 50% of data.

Use the mean

to describe the center when the data set is symmetric and has no outliers, as it takes all values into account.

Use the median

to describe the center when the data set is skewed or contains outliers, as it is less affected by extreme values.

Use the IQR

when describing the spread when the data set has outliers or is skewed

Use the range

when describing the spread when the data is symmetrically distributed with no significant outliers