Foot drop Common Causes. Introduction: This information shows the various causes of Foot drop, and how common these diseases or conditions are in the general population. This is not a direct indication as to how commonly these diseases are the actual cause of Foot drop, but gives a relative idea as to how frequent these diseases are seen overall.
Variability refers to how spread out a group of data is. The common measures of variability are the range, IQR, variance, and standard deviation. Measures of variability are descriptive statistics, which means they can only be used to describe the study data.
Definition of Variance. Variance is a statistical measure that tells us how measured data vary from the average value of the set of data. In other words, variance is the mean of the squares of the deviations from the arithmetic mean of a data set.