n-1 Explained Conceptually

In this video I answer the common question of why we divide by n-1 when calculating variance from a sample, known as Bessel’s Correction. I focus on conceptual understanding of why this adjustment is needed and why n-1 is the … Read More

Dispersion for Nominal Data: The Variation Ratio

In this video I describe how we can describe dispersion or variability in nominal data by calculating a variation ratio. This is a simple measure of spread that tells us the frequency of scores that differ from the mode, which … Read More

Understanding Central Tendency

In this video I explain the strengths and limitations of the 3 measures of central tendency: the mean, the median, and the mode. This is part of a key theme of statistics, which is the importance of the choices researchers … Read More

Scales of Measurement or Types of Data

In this video I describe the 4 scales of measurement proposed by Stanley Smith Stevens, which have become the standard way of defining types of data. These include nominal, ordinal, interval, and ratio. I discuss the defining features of each, … Read More