One way to get column stats is with summarize():

dt = Open("$ENGLISH_SAMPLE_DATA/Big Class.jmp");

//Get column stats

summarize(

sigma=StdDev(:height),

avg = mean(:height)

);

siglow = avg - 3 * sigma;

sighigh = avg + 3 * sigma;

//make distribution

Distribution(

Continuous Distribution( Column( :height ), Count Axis( 1 ) ),

SendToReport(

Dispatch(

{"height"},

"1",

ScaleBox,

{

Min( 45 ), Max( 78), Inc( 5 ),Minor Ticks( 1 ),

Add Ref Line( eval(siglow), Dotted, "Black","-3sd" ),

Add Ref Line( eval(sighigh), Dotted, "Black","+3sd" )

}

)

)

);