Comparing data sets
In a nutshell
Data can be compared in two ways: measures of location and measures of spread.
Measures of location
To compare data using measures of location, you can use the mean or the median.
Measures of spread
To compare data using measures of spread, you can use the standard deviation or the interquartile range.
Comparing data
When comparing data, you must compare a measure of location and a measure of spread.
You can either compare the means and the standard deviations or the medians and the interquartile ranges - the latter of which is preferred if the given data has extreme values.
Example 1
Katie averaged 3.6 hours of reading last month, with a standard deviation of 0.2hours.
Knowing that the average reading time for someone her age is 1.4 hours with a standard deviation of 0.5 hours, compare Katie's reading time to the average.
Katie averaged more reading time than people her age. However, her values are less spread than the average.