# What is a bad standard deviation?

## What is a bad standard deviation?

For an approximate answer, please estimate your coefficient of variation (CV=standard deviation / mean). As a rule of thumb, a CV >= 1 indicates a relatively high variation, while a CV < 1 can be considered low. ... Remember, standard deviations aren't "good" or "bad". They are indicators of how spread out your data is.

## What can affect standard deviation?

The standard deviation is affected by outliers (extremely low or extremely high numbers in the data set). That's because the standard deviation is based on the distance from the mean. And remember, the mean is also affected by outliers. The standard deviation has the same units as the original data.

## Is standard deviation reliable?

Smaller standard deviations reflect more clustered data. More clustered data means less extreme values. A data set with less extreme values has a more reliable mean. The standard deviation is therefore a good measure of the reliability of the mean value.

## Why is lower standard deviation better?

Low standard deviation means data are clustered around the mean, and high standard deviation indicates data are more spread out. A standard deviation close to zero indicates that data points are close to the mean, whereas a high or low standard deviation indicates data points are respectively above or below the mean.

## What would a standard deviation of zero mean?

When the standard deviation is zero, there is no spread; that is, the all the data values are equal to each other. The standard deviation is small when the data are all concentrated close to the mean, and is larger when the data values show more variation from the mean.

## Is the standard deviation an average?

The average deviation, or mean absolute deviation, is calculated similarly to standard deviation, but it uses absolute values instead of squares to circumvent the issue of negative differences between the data points and their means. ... Calculate the average of the absolute values of those differences.