Repeatability

Data

Measurementsrows (max 500)

No.	Measured value $x_i$	Delete row
1
2
3
4
5
6
7
8
9
10

Use the up and down arrows to move between cells. Enter moves to the next row, and adds one at the bottom. Pasting a range copied from Excel or a spreadsheet fills several rows at once.

Reference value

Reference value (target)

x_0

Used to work out the bias $b$ and the overall accuracy. Left empty, only the spread — the repeatability — is calculated.

Result

Item	Symbol and formula	Value
Number of values	$n$	-
Mean	$\bar{x}$ $\displaystyle = \frac{1}{n}\sum x_i$	-
Median	$\tilde{x}$	-
Minimum	$x_{min}$	-
Maximum	$x_{max}$	-
Range	$R$ $\displaystyle = x_{max} - x_{min}$	-
Sum of squared deviations	$S$ $\displaystyle = \sum (x_i - \bar{x})^2$	-
Sample standard deviation	$s$ $\displaystyle = \sqrt{\frac{S}{n-1}}$	-
Population standard deviation	$\sigma$ $\displaystyle = \sqrt{\frac{S}{n}}$	-
Bias	$b$ $= \bar{x} - x_0$	-
Repeatability	$\displaystyle \pm \frac{x_{max} - x_{min}}{2}$	-
±1σ (about 68.3 %)	$\pm s$	-
±2σ (about 95.4 %)	$\pm 2s$	-
±3σ (about 99.7 %)	$\pm 3s$	-

Press Calculate to see the values.

Notes

Empty cells are treated as not entered and left out. Cells that cannot be read as a number are also left out, and their row numbers are shown in red.