Population Variance and Standard Deviation

Key differences between population variance and standard deviation are:

Aspect

Standard Deviation

Population Variance

Definition

Measures the spread of data points in a population from the population mean.

Measures the dispersion of data points in a population from the population mean.

Formula

[Tex]\sigma^2 = \frac{1}{N} \sum_{i=1}^{N} (x_i – \mu)^2[/Tex]

[Tex]\sigma = \sqrt{\frac{1}{N} \sum_{i=1}^{N} (x_i – \mu)^2}[/Tex]

Units

Squared units of the original data (e.g., square meters, square dollars).

Same units as the original data (e.g., meters, dollars).

Bias Correction

Uses N in the denominator.

Uses N−1 in the denominator.

Representation

σ2

σ

Sensitivity to Outliers

Less sensitive, as it squares differences before averaging.

More sensitive, as it considers absolute differences.

Population Variance

Population variance is a fundamental concept in statistics that quantifies the average squared deviation from the mean of a set of data points in a population. It is a measure of how spread out a group of data points is.

There are two types of data available, namely, ungrouped and grouped data. Thus, there are two formulas to calculate the population variance. In this article, we will learn more about population variance, its formulas, and various associated examples.

Table of Content

  • What is Population Variance?
  • Formula of Population Variance
    • Ungrouped Data
    • Grouped Data
  • Population Variance and Sample Variance
  • Population Variance and Standard Deviation
  • Solved Problems on Population Variance
  • Practice Questions on Population Variance
  • FAQs on Population Variance

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What is Population Variance?

Population variance determines how far each data point is from the population mean. It can be defined as the average of the square of the deviations from the data’s mean value. If all data points are very close to the mean, the variance will be small; if data points are spread out over a wide range, the variance will be larger....

Formula of Population Variance

The population variance is a fundamental statistical measure that quantifies the dispersion or variability of a dataset around its mean. Whether dealing with grouped or ungrouped data, understanding the population variance formula is essential for analyzing and interpreting the spread of data points within a population....

Population Variance and Sample Variance

The table gives the differences between the population variance and sample variance:...

Population Variance and Standard Deviation

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Solved Problems on Population Variance

Problem 1: Suppose we have the heights (in centimeters) of five students: 160, 165, 170, 175, and 180. The mean height is 170 cm. Calculate the population variance....

Practice Questions on Population Variance

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FAQs on Population Variance

What’s the difference between population variance and sample variance?...