In 41 patients, all hyperfunctioning parathyroid tissue was resected at the time of surgery and confirmed by a corresponding decrease in the intraoperative postexcision rapid PTH determination as well as by subsequent normalization of postoperative serum calcium and PTH levels and resolution of clinical symptoms.
In other words, the standard deviation Ï (sigma) is the square root of the variance of X; i.e., it is the square root of the average value of (X â Î¼) 2. The standard deviation of a (univariate) probability distribution is the same as that of a random variable having that distribution.
Standard deviation: It is the square root of mean/average of squared deviations of data point from mean i.e. we subtract the mean from each data point; take it's square value (which is again non-negative); sum it up and divide by the number of observations. Surely, standard deviation is a better & most commonly used measure of variation.