[Overview][Constants][Types][Classes][Procedures and functions] Reference for unit 'math' (#rtl)

meanandstddev

Return mean and standard deviation of array

Declaration

Source position: line 0

procedure meanandstddev(

  const data: array [] of float;

  var mean: float;

  var stddev: float

);

procedure meanandstddev(

  const data: PFloat;

  const N: LongInt;

  var mean: float;

  var stddev: float

);

Description

meanandstddevcalculates the mean and standard deviation of dataand returns the result in meanand stddev, respectively. Stddev is zero if there is only one value. The second form accepts a pointer to an array of Nvalues.

Errors

None.

See also

mean

  

Return mean value of array

sum

  

Return sum of values

sumofsquares

  

Return sum of squares of values

momentskewkurtosis

  

Return 4 first moments of distribution

Example

Program Example28;

{ Program to demonstrate the Meanandstddev function. }

Uses math;

Type
  TExArray = Array[1..100] of Extended;

Var
  I : Integer;
  ExArray : TExArray;
  Mean,stddev : Extended;

begin
  Randomize;
  for I:=low(ExArray) to high(ExArray) do
    ExArray[i]:=(Random-Random)*100;
  MeanAndStdDev(ExArray,Mean,StdDev);
  Writeln('Mean       : ',Mean:8:4);
  Writeln('StdDev     : ',StdDev:8:4);
  MeanAndStdDev(@ExArray[1],100,Mean,StdDev);
  Writeln('Mean   (b) : ',Mean:8:4);
  Writeln('StdDev (b) : ',StdDev:8:4);
end.