void StatNormalPlot(TVec *Data, TVec *XDrawVec, TVec *YDrawVec, double &MinX, double &MaxX, double &MinY, double &MaxY, TVec *StdErrs = null, const bool DataSorted = true);
Constructs the Normal Probability Chart.
| # | Name | Type | Description |
|---|---|---|---|
| 1 | Data | TVec * | Data to be drawn. The assumption is data values are sorted. |
| 2 | XDrawVec | TVec * | Returns normal probability plot horizontal values to be drawn - > estimated quantiles from Data vector or in this case sorted Data values. |
| 3 | YDrawVec | TVec * | Returns normal probability plot vertical values to be drawn - > Values are generated from theoretical standard normal distribution with parameters mu=0, sigma^2=1. |
| 4 | MinX | double & | Returns slope line start X point, XDrawVec 25th percentile. These value are used by Dew.Stats.Tee.ProbabilityPlot series. |
| 5 | MaxX | double & | Returns slope line end X point, XDrawVec 75th percentile. These value are used by Dew.Stats.Tee.ProbabilityPlot series. |
| 6 | MinY | double & | Returns slope line start Y point, YDrawVec 25th percentile. These value are used by Dew.Stats.Tee.ProbabilityPlot series. |
| 7 | MaxY | double & | Returns slope line end Y point, YDrawVec 75th percentile. These value are used by Dew.Stats.Tee.ProbabilityPlot series. |
| 8 | StdErrs = null | TVec * | Standard error |
| 9 | DataSorted = true | const bool | If true, algorithm assumes Data is already sorted in ascending order. If Data is not sorted, you must set this parameter to false so that internal algorithm will automatically do the sorting. |
Remarks:
How to construct Normal distribution probability plot?
- If needed, Data values are sorted (DataSorted parameter must be set to false).
- Abscissa drawing values are formed by estimated data quantiles - ordered Data values. After calculation they are copied to XDrawVec. TMtxVecBase::Length and TMtxVec::Complex properties of XDrawVec are adjusted automatically.
- Ordinate drawing values are formed by using theoretical probability
pi.e the soZvalues. After calculation they are copied to YDrawVec. TMtxVecBase::Length and TMtxVec::Complex properties of YDrawVec are adjusted automatically. - XDrawVec and YDrawVec 25th and 75th percentile points are used to construct a reference line. Drawing points departures from this straight line indicate departures from normality.
The normal probability plot is used to answer the following questions:
- Are the data normally distributed?
- What is the nature of the departure from normality (data skewed, shorter than expected tails, longer than expected tails)?
See Also: Dew.Stats.Tee.ProbabilityPlot
Declared in Dew::Stats::Units::StatProbPlots · Dew.Stats/Units.StatProbPlots.h · Cross-compiler