STDEV Function (Functions in Excel)

Values		Values		Values
10		10		10
10		10		11
9		11		9
10		10		12
0.5		0.5		1.2909944
=STDEV(C4:C7)		=STDEV(E4:E7)		=STDEV(G4:G7)

What Does It Do ?

This function calculates the sample population standard deviation of a list of values.

A sample population is used when the list of values represents a sample of a population.

Syntax

=STDEV(Range1,Range2,Range3 through to Range30)

Formatting

No special formatting is needed.

Example

The table below was used by a company interested in buying a new machine

to pack washing powder.

Three machines were short listed and allow to run for a day.

At the end of the day four boxes of soap powder were picked at random from the production

of each machine.

The boxes were weighed and the =STDEV() function used as these boxes only represented

a sample of the complete days production.

The machine with the smallest deviation was the most consistent.

	Soap Powder Box Filling Machine Test Results
	Test 1	Test 2	Test 3	Test 4	Variance
Machine 1	1.4	1.5	1.6	1.5	0.0816	=STDEV(D34:G34)
Machine 2	1.5	1.5	1.4	1.5	0.0500	=STDEV(D35:G35)
Machine 3	1.5	1.6	1.7	1.8	0.1291	=STDEV(D36:G36)
				The smallest deviation is :	0.0500	=MIN(H34:H36)
				The machine with the smallest deviation is :	Machine 2
					=INDEX(C34:C36,MATCH(MIN(H34:H36),H34:H36,0))

Explanation of formula:
This finds the lowest value.	=MIN(H34:H36)
This finds the position of the lowest value.	=MATCH(MIN(H34:H36),H34:H36,0)
This looks down the Machine column to	=INDEX(C34:C36,MATCH(MIN(H34:H36),H34:H36,0))
find the machine name.

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