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Learn Sample Variance | Variance and Standard Deviation
Learning Statistics with Python

bookSample Variance

Now explore sample variance. The concept is similar to population variance, but the formula differs slightly because the data represents only a subset of the entire population.

Formula

variance=βˆ‘i=1n(xiβˆ’xΛ‰)2nβˆ’1\text{variance} = \frac{\sum^n_{i=1}(x_i-\bar{x})^2}{n-1}

Where:

  • nn - sample size;
  • ii - index of each element;
  • xix_i - each element;
  • xΛ‰\bar{x} - sample mean value.

Look at the example of variance rounded to two decimal points for the column 'salary_in_usd':

The variance of the column 'salary_in_usd' is 5034932663.18

Variance Key Note

The variance of the 'salary_in_usd' column is quite substantial, indicating that the values in this column are widely spread out.

Note
Note

The greater the variance, the more the values are scattered.

question mark

Select the one with lower variance from the graphs with an equal number of observations and identical mean values.

Select the correct answer

Everything was clear?

How can we improve it?

Thanks for your feedback!

SectionΒ 3. ChapterΒ 2

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bookSample Variance

Swipe to show menu

Now explore sample variance. The concept is similar to population variance, but the formula differs slightly because the data represents only a subset of the entire population.

Formula

variance=βˆ‘i=1n(xiβˆ’xΛ‰)2nβˆ’1\text{variance} = \frac{\sum^n_{i=1}(x_i-\bar{x})^2}{n-1}

Where:

  • nn - sample size;
  • ii - index of each element;
  • xix_i - each element;
  • xΛ‰\bar{x} - sample mean value.

Look at the example of variance rounded to two decimal points for the column 'salary_in_usd':

The variance of the column 'salary_in_usd' is 5034932663.18

Variance Key Note

The variance of the 'salary_in_usd' column is quite substantial, indicating that the values in this column are widely spread out.

Note
Note

The greater the variance, the more the values are scattered.

question mark

Select the one with lower variance from the graphs with an equal number of observations and identical mean values.

Select the correct answer

Everything was clear?

How can we improve it?

Thanks for your feedback!

SectionΒ 3. ChapterΒ 2
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