Z Scores were a concept I had trouble with in University. It’s actually not as difficult as they’re made out to be. I’ll spare you the complicated introduction (as I’m sure you got one from both your textbook and your Professor), but remember that z-scores show you the distance between your score and the mean,…
Dispersion and Variability (Standard Deviation)
The topics dispersion and variability (or variance) describes the “spread” of data in a distribution. This article explains how to compute the variance and the standard. The first measure of dispersion to look at is the variance. Let’s look at the data set below: X Values 4 5 2 7 Steps to Calculate Variance:…
Measures of Central Tendency
The measures of central tendency are processes for determining what the central value in a dataset is. The most common is the arithmetic average, or mean – so this value has come to be known as simply the average. The three measures of central tendency are mean, median and mode. Mean To calculate the mean…
Frequency Distributions
Frequency distributions are a simple way of organizing data based on how many each item has occurred. This can be used for individual values or for age ranges. The steps for making a frequency distribution are pretty simple. Let’s take a set of 20 students and their ages: 18 17 17 18 15 15 17…
Delphi Technique
Introduction There are a number of techniques for making predictions or analysis. It is particularly useful in governments, public policy, and other areas where facts may be disputed but generally based on a set of common foundational knowledge. Examples of this type include economics (where the same economic principles may be expressed differently by country),…