SummarizingStatisticalData

ProbabilityAndStatistics -- StatisticalRegularity

PlanningResearch -- InterpretingStatisticalData

In general, statistical data can be described as a list of subjects or Units and the data associated with each of them. Although most research uses many data types for each Unit, we will limit ourselves to just one data item each for this simple introduction.

We have two objectives for our summary:

1. How do the data for different Units seem similar? Statistical textbooks call the answer to this question a measure of CentralTendancy.
2. How do they differ? This is often called StatisticalVariability?.

When we are summarizing a quantity like length or weight or age, it is common to answer the first question with the MeaN, the MediaN, or the MoDe. Sometimes, we choose specific values from the CumulativeDistributionFunction? called QuanTiles?.

The most common measures of variability for QuantitativeData? are the VarianCe?, its square root, the StandardDeviation?, the RanGe?, InterQuartileRange?, and AbsoluteDeviation?.