Summary are a single value summarizing a array of data.
They are:
They are an important element of descriptive analysis
One of the most important tools for summarizing data is to display it visually. See the Anscombe's quartet to understand why ?
From a summary, you can make an inference on a individual without looking at the distribution
Have a look at the distribution before jumping to the summary (in order to not make a stereotype)
Same as: Function - (Aggregate | Aggregation)
In order to summarize a set of data, we want to use one single number or value to describe where it is centred.
This single value can be calculated through one of the following (statistic|measure) of center:
Another important element of a data set is how it is spread.
Measures of spread:
Apache Math Package specifically DescriptiveStatistics