# Author Archives: Bryan Rucklos

## Confidence Interval for Paired Means

The testing method of paired means  is used to compare the means of two variables for a single group. It is often referred to as the paired difference  test since it tests whether the difference between two variables within the single group. It is important to note that since the data is “paired” it is not independent. […]

## Mean

Within a data set, the mean is simply the average of n numbers in the set. It is commonly used to measure central tendencies and is calculated by taking the sum of all the numbers in the set and dividing that sum by the number of data points, n. This can be viewed symbolically for the sample mean, x […]

## Contingency Tables

A contingency table is a statistical table that displays the frequencies of data elements according to defined categorical variables. The table consists of columns and rows which each represent a separate categorical variable and is used to display frequency relationships between two separate categorical variables. Often in the margins there are also totals of each row or column that […]