In an earlier article, we examined a large dataset of rating scale data. After analyzing over 100,000 individual responses from 4,048 multipoint items across 25 studies, we reported the typical standard deviations for five-, seven-, and eleven-point items.| measuringu.com
The standard deviation is the most common measure of variability. It’s less intuitive than measures of central tendency such as the mean, but it plays an essential role in analysis and sample size planning.| MeasuringU
When working with UX metrics (e.g., rating scale data) you need to consider both the average and the variability of the responses.| MeasuringU
In math class, we spend a lot of time learning fractions because they are so important in everyday life (e.g., budgeting, purchasing at the grocery store). Fractions are also used extensively in UX research (e.g., the fundamental completion rate is a fraction), typically expressed as percentages or proportions. Unfortunately, fractions are also hard to learn, and as it turns out, they are not the easiest to statistically analyze.| MeasuringU
