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. This might be …

Calculating standard deviation step by step Standard deviation of a population Mean and standard deviation versus median and IQR Concept check: Standard deviation Statistics: Alternate variance …

Introduction The questions below are designed to help you think deeply about standard deviation and its formula. Unlike most questions on Khan Academy, some of these questions aren't graded by a …

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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.

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.

A large sample of females had their systolic blood pressure measured. The mean blood pressure was 125 millimeters of mercury and the standard deviation was 10 millimeters of mercury. Which normal …

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 …