Machine LearningLesson 71Free preview

Standard Deviation

This lesson is part of Python · All levels

Summary

The standard deviation measures how much data is spread around the mean. A small value means data is accumulating close to the mean, whereas a large value means data is very scattered. His calculation is rooted in the square of the average difference of each data to the mean, called the variance. NumPy distinguishes population count with ddof=0 and sample with ddof=1.

Key points

Standard deviation is the measure of the spread of data against the mean
Variance is the square of the difference from mean; standard deviation is the square root of the variance.
Small data means close data, large data means spreading data.
Np.std() using ddof=0 (population) and ddof=1 (sample)

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