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 from the …

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 deviation.

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 (mean) and …