Measures of dispersion, data range, variation of mean, standard deviation, variance, coefficient of variance, standard error of mean, applications of standard error of mean, types of measures of dispersion, quartile deviation, coefficient of quartile deviation, mean deviation, merits and demerits of standard deviation, types of dispersion and their significance, variance and standard error of mean with suitable example, standard error and standard error of mean with suitable example, in routine diagnostic investigation the following results were obtained, compute the mean , standard deviation, and coefficient of variance, numerical of biostatics