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 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.

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 range is easy to calculate—it's the difference between the largest and smallest data points in a set. Standard deviation is the square root of the variance.

What are z-scores? A z-score measures exactly how many standard deviations above or below the mean a data point 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.

Practice calculating and interpreting the mean and standard deviation of a discrete random variable.

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 …

A standard deviation close to 0 indicates that the data points tend to be close to the mean (shown by the dotted line). The further the data points are from the mean, the greater the standard …

We learn how to calculate the mean and standard deviation of a discrete random variable. The concept of a random variable is explained, along with methods to calculate its expected value …