topic Re: Average the first 100 rows and the last 100 rows of a JMP column. in Discussions

Average the first 100 rows and the last 100 rows of a JMP column.

SpannerHead — Thu, 12 Mar 2026 14:31:54 GMT

I have a noisy curve where I need to take average of the extremes and compare to the minimum value. Thought this would work but doesn't.

Col Mean( :Column_Name W[Index( 1, 100 )] ) + Col Mean( :Column_Name[N Rows() - 99 :: N Rows()] ) / 2

Re: Average the first 100 rows and the last 100 rows of a JMP column.

txnelson — Thu, 12 Mar 2026 15:15:34 GMT

Here is one way of handling the issue

Names Default To Here( 1 );
dt = 
// Open Data Table: Semiconductor Capability.jmp
// → Data Table( "Semiconductor Capability" )
Open( "$SAMPLE_DATA/Semiconductor Capability.jmp" );
column_name = "NPN1";
Col Mean( If( Row() <= 100, Column( column_name ), . ) ) + Col Mean(
	If( Row() >= N Rows() - 99,
		Column( column_name ),
		.
	)
) / 2;


// I think this is a better formula to calculate the mean of the extremes
Col Mean( If( Row() <= 100 | Row() >= N Rows() - 99, Column( column_name ), . ) );

Re: Average the first 100 rows and the last 100 rows of a JMP column.

MathStatChem — Thu, 12 Mar 2026 15:27:47 GMT

Try this

(Mean( :Z[Index( 1, 100 )] ) + Mean( :Z[Index( N Rows() - 99, N Rows() )] )) / 2

Re: Average the first 100 rows and the last 100 rows of a JMP column.

MathStatChem — Thu, 12 Mar 2026 15:28:15 GMT

I used "Z" as the column name.