The standard deviation formula may look confusing, but it will make sense after we break it down. In the coming sections, we'll walk through a step-by-step interactive example.

The standard deviation formula may look confusing, but it will make sense after we break it down. In the coming sections, we'll walk through a step-by-step interactive example.

Standard deviation measures how far apart numbers are in a data set. Variance, on the other hand, gives an actual value to how much the numbers in a data set vary from the mean.

The formula we use for standard deviation depends on whether the data is being considered a population of its own, or the data is a sample representing a larger population.

Finally, we'll take the square root of the variance to get the standard deviation. The complete step-by-step method is also explained. Created by Ashish Gupta.

To find the z-score of the sample mean, you use the formula: Z = X - μ / (σ / sqrt (n)), where X is the sample mean, μ is the population mean, σ is the population standard deviation, and n is …

A z-score is an example of a standardized score. A z-score measures how many standard deviations a data point is from the mean in a distribution.

Think about it: remember how the standard deviation squared is the sum of all the points minus the mean squared? Since it is squared, there is no negative numbers, and only the distance …

Practice calculating sample standard deviationWelcome to Khan Academy! So we can give you the right tools, let us know if you're a...

Now, if we knew the standard deviation of this population, we would know what the standard deviation of the sampling distribution of our statistic is. It would be equal to the standard …