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Mar
Mean And Std Deviation. Standard deviation is a kind of typical distance from the mean usually slightly larger than the average distance from the mean. Mean is basically the simple average of data. Since the standard deviation can be thought of measuring how far the data values lie from the mean we take the mean and move one standard deviation in either direction. If we multiply all values in the input set by a number 7 both mean and the standard deviation is multiplied by 7.
The mean for this example was about 492 and the standard deviation was 17. 10 20 2. If the data points are further from the mean there is a higher deviation within the data set. Like the variance if the data points are close to the mean there is a small variation whereas the data points are highly spread out from the mean then it has a high variance. If we add or subtract a number say 7 to all values in the input set the mean is increased or decreased by 7 but the standard deviation doesnt change. It is a popular measure of variability because it returns to the original units of measure of the data set.
Thus the more spread out the data the higher the standard deviation.
Standard deviation is used to measure the volatility of a stock. Select STDEVS for a sample from the the Statistical category. Examples of measures of dispersion are the variance. What does a standard deviation of 14 mean. The standard deviation indicates a typical deviation from the mean. So with ratings on 1 5 you might call 14.