Prediction Ellipse Function

SAS_Timber — Mon, 24 Jun 2024 07:30:48 GMT

Hi users and members, is it possible to get the function of a prediction ellipse or at least the length, height and centre? If yes, then how do i add this to my code?

Code:

/* 95% prediction ellipse */
proc sgplot data=combined_values;
scatter x=new_x y=new_y / markerattrs=(symbol=circlefilled);
ellipse x=new_x y=new_y / alpha=0.05 lineattrs=(thickness=2 color=red) type=prediction;
title "diagram";
xaxis label="x-Werte" min=0 max=&max_val;
yaxis label="y-Werte" min=0 max=&max_val;
run;

thanks for your help!

Re: Prediction Ellipse Function

PaigeMiller — Mon, 24 Jun 2024 12:07:55 GMT

@Rick_SAS has the answer!

https://blogs.sas.com/content/iml/2014/07/23/prediction-ellipses-from-covariance.html

Why do you need this prediction formula, what would you do with it if you had it? If you want to determine if additional points (not the ones used to create the ellipse) are within the ellipse, you can just add these additional points to the plot. Example:

data additional;
    height1=60; weight1=80; output;
    height1=70; weight1=95; output;
    height1=80; weight1=50; output;
run;

data class;
    set sashelp.class additional;
run;

proc sgplot data=class;
scatter x=height y=weight / markerattrs=(symbol=circlefilled);
ellipse x=height y=weight / alpha=0.05 lineattrs=(thickness=2 color=red) type=predicted;
scatter x=height1 y=weight1 / markerattrs=(symbol=plus);
run;

topic Prediction Ellipse Function in SAS Programming

Prediction Ellipse Function

Re: Prediction Ellipse Function