meansdevn

meansdevn

The meansdevn function returns the mean and standard deviation of a general lua table that may contain a multi-dimensional array or a mixture of numbers, strings, named keys, and sub-tables. Only numeric values found in the table are used in the calculation. The meann function returns only the mean value. The related meansdev function calculates the mean and standard deviation of a 1-dimensional array, CImage, or list of numbers. Since an array is a specific type of table that contains only numbers or sub-tables, this function can also be used for arrays.

Syntax

nMean, nStdDev = meansdevn( tbl )

tbl is a general lua table.

nMean is the mean of the data.

nStdDev is the standard deviation of the data.

Examples

The following script returns the mean and standard deviation of a 1-dimensional array containing 1 million random numbers.

t = random( 1000000 )	-- create an array of numbers
v, s = meansdevn( t )	-- find the mean & standard deviation
Printf("Mean=%lg, sdev=%lg\n", v, s )	-- list the result

The next example computes the mean and standard deviation of an ugly, complex table:

t = { 6, -2, 15, "a", {5,"b"}, c="5.4" }
v, s = meansdevn(t)	-- find the mean and standard deviation
Printf("M= %lg, S= %lg\n", v, s )	-- result: Mean = 6, based on only 4 numbers

Syntax

Examples

Related Topics