JSL Script - Grab Prediction Formula Result

ngodfrey

Hello,

 

I am trying to obtain the predicted value after setting the X's in a prediction formula.

For example, if Y = X1 + X2, I want to create a new row, set X1 = 2 and X2 = 4 and grab the predicted value of Y = 6.

 

I thought the easiest way to do this would be to save the prediction formula into a new set of columns.

I would then add a new row and set all the X's.

Then, simply access the row value of the prediction formula.

However, this does not work. The log shows that the value returns a '.'. If I run the script twice, so multiple rows are created, the value returns correctly. If I add two rows and run the script only once, I still get the 'null' or '.' in the log file. There appears to be a reason for JMP needing to run the script twice to obtain the predicted formula result of a newly added row with set X values.

 

Is there a better way to grab predicted values from prediction formulas using scripts?

 

Thank you,
Nate

ian_jmp

Details depend on the platform you use, but this shows the basic idea:

NamesDefaultToHere(1);
// Get some data
dt = Open("$SAMPLE_DATA/Big Class.jmp");
biv = dt << Bivariate(X(:height), Y(:weight));
// Do a regression
biv << fitLine;
/// Save the prediction formula column
biv << (curve[1] << savePredicteds);
// Add a new observation (row) that we want to predict for
Wait(2);
dt << addRows(1);
// Give predictor values and get the prediction back
Column(dt, "weight")[NRow(dt)] = 160;
Column(dt, "height")[NRow(dt)] = 65;