To understand how spread out a set of data points can be, we need to measure the variation. The…

There is an important distinction between a sample of data and population of data. So, let’s take a research…

Previous article discussed the basic contingency table of proportions and percentages. People often want to ask more about relationships…

One of the way to measure the variability is to calculate the difference of each observation from the mean.…

We have covered major measures of center and location—mean, median, and mode—we now turn to other important measures: percentiles…

Variance represents the average of the squared deviations from the mean. Because we square the deviations, the variance is…