Roadmap Tutorial API's: XYGraph Axes etc Series Stats

TxyGraph Statistics information

Information in TDataSeries

TDataStats = record
   comment:String;
   error:boolean;
   count:integer;
   mean, median, mode, Total, SD, Skew, Kurtosis,
   lowquintile, highquintile, lowquartile, highquartile:double;
end;

error is set to true if an error was encountered during analysis. Comment will contain a text description of the error. Some or all of the other values may be invalid if an error was encountered, they will be set to zero in this case

information in TCompStats

TCompStats= record
  comment:String;
  error:boolean;
  Rsquared, PearsonR, PRMin, PRMax, RSqMin, RSqMax, PValue,
  RegSlope, regintercept, RegSlope2, SlopeSD, IntSD: Double;
end;

Error is set to true if an error was encountered during analysis. Comment will contain a text description of the error. Some or all of the other values may be invalid if an error was encountered, they will be set to zero in this case

Variable description

References: Numerical recipes in Pascal and Intuitive Biostatistics, H.M.Motulsky

Regression types and meaning of value stored in "r"

Type identifier value of r in series data
none rg_none rubbish
Least Squares rg_linear predicted value
Passing Bablok rg_passingBablok predicted value
Running Average rg_runningAverage average at point
Spline rg_spline 2nd Differential at point
Distance Weighted Least Squares (DWLS) rg_DWLS rubbish
Quadratic rg_Quadratic predicted value

References and comments on regression procedures:

Passing / Bablok Regression.

Bablok W. and Passing, H.: "Application of Statistical Procedures in Analytical instrument testing", J. Auto. Chem. v7, 1985, pp74-79. Suited for analytical comparisons - no assumption that x is without error.

Linear/Quadratic Regression. Devore, JL.: "Probability and Statistics for the engineering and Scientists", Duxbury Press, Belmont, Ca. 1990, pp460 - 461, or p516 - 517. I copied his quadratic correctly but it doesn't work well. Any body got a fix?

Running Average - applications in QA procedures. No reference

Distance Weighted Least Squares line fitting McLain DH.: "Drawing Contours from arbitrary data points." Comp. J., v17, 1973? pp 318 - 324. His discussion there is for 3d fitting - The weighting is discussed there. The least squares bit came off the top of my head, and I missed something, because it doesn't work quite as it should - see the comment in the main routine

Spline algorithm - adapted from the "Numerical Recipes in Pascal" toolkit