2-sided refers to the direction of the effect you are interested inIn most practical scenarios the 1-sided number is the relevant one. Consider the following linear. Normal Distribution Diagram 2 Standard Deviation Normal Distribution Explained Moreover this function accepts a single argument. . For a normal distribution this table summarizes some common percentiles based on standard deviations above the mean M mean S standard deviation. Within standard deviation is an estimate of the variation within the subgroups. When standard deviation errors bars overlap quite a bit its a clue that the difference is not statistically significant. Alternatively you can calculate the coefficient of variation which uses. So both Standard Deviation vs Mean plays a vital role in the field of finance. Consequently the standard deviation is the most widely used measure of variability. Here σ M represents the SE. Read more of...