How to use the STDEV.P function

What is the STDEV.P function?

The STDEV.P function returns standard deviation based on the entire population. STDEV.P is an abbreviation of standard deviation population. The STDEV.P function and the STDEV.S functions replaces the outdated STDEV function.

What is Standard Deviation?

Standard deviation tells you how far from the average values are spread out. Both charts above have numbers and an average plotted, they share the exact same average however, the numbers are not the same.

Chart A above shows that the values are more spread out than the values in chart B. Chart A has a standard deviation of 23.45256334, standard deviation for chart B is 5.207075606. Standard deviation is fundamental in statistics.

What is the difference between the STDEV.P function and the STDEV.S function?

STDEV.P function calculates the standard deviation for a population and the STDEV.S function calculates the standard deviation for a sample. STDEV.P uses the count of all values (n) in the denominator.
STDEV.S uses (n-1) in the denominator (Bessel's correction). This accounts for the difference between sample variance and population variance in statistics. STDEV.S is better for sample inferential statistics.

STDEV.P math formula:

STDEV.S math formula:

When to use the STDEV.P function and the STDEV.S function?

Use STDEV.P if you have the full population data. Use STDEV.S if you have a sample of limited data from a larger population. STDEV.P will result in a lower standard deviation compared to STDEV.S on the same data.

Sample standard deviation is considered a better estimate for inferring population parameters.

What is inferring population parameters?

Population parameters refer to the actual values of statistics that describe an entire population, such as the population mean or standard deviation. However, the true population parameter values are often not known.

What is sample inferential statistics?

Sample inferential statistics are methods that allow using statistics calculated on a sample of data to infer the unknown population parameters.

For example:

• The sample mean can be used to estimate the population mean.
• The sample standard deviation can estimate the population standard deviation.

STDEV.P function Syntax

STDEV.P(number1, [number2], ...)

STDEV.P function Arguments

number1	Required. The first number argument that represents a population.
[number2]	Optional. Up to 253 additional number arguments.

STDEV.P function example

Formula in cell D3:

The STDEV.P function ignores logical values and text values.

For large sample sizes, STDEV.S and STDEV.P return approximately equal values.

How is the output from the STDEV.P function calculated?

The STDEV.P function is entered in cell D3, here is how the function calculates the output:

x ̅ is the average.
n is how many values.

Step 1 - Calculate the average

137+139+141+105+139+124+126+146+105+101 = 1263

1263/10 = 126.3

Step 2 - Subtract the average and square the result for all values

(137-126.3)^2+(139-126.3)^2+(141-126.3)^2+(105-126.3)^2+(139-126.3)^2+(124-126.3)^2+(126-126.3)^2+(146-126.3)^2+(105-126.3)^2+(101-126.3)

becomes

(10.7)^2+(12.7)^2+(14.7)^2+(-21.3)^2+(12.7)^2+(-2.3)^2+(-0.299999999999997)^2+(19.7)^2+(-21.3)^2+(-25.3)

becomes

114.49+161.29+216.09+453.69+161.29+5.29+0.0899999999999982+388.09+453.69+640.09

and returns

2594.1

Step 3 - Divide with the total count

2594.1/10 equals 259.41

Step 4 - Square root the result

259.41^(1/2) equals 16.1062099824881

Recommended articles

• Standard Deviation Calculator
• Standard Deviation Formulas

Functions in 'Statistical' category

The STDEV.P function is one of 74 functions in the 'Statistical' category.

Excel function categories

Excel categories

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