Confidence in Std Deviation

vince_faller

Is there a way to graph Confidence (say .9) in a bunch of Std Deviations other than digging through each of their distributions?  Maybe I'm just brain-dead this morning.

*Edit*  Right now I'm just doing this but I feel like there is a better way. 

x = current report();

est = (x << xpath("//OutlineBox[text() = 'Confidence Intervals']/TableBox/NumberColBox[1]/NumberColBoxItem[2]/text()"));

LCI = (x << xpath("//OutlineBox[text() = 'Confidence Intervals']/TableBox/NumberColBox[2]/NumberColBoxItem[2]/text()"));

UCI = (x << xpath("//OutlineBox[text() = 'Confidence Intervals']/TableBox/NumberColBox[3]/NumberColBoxItem[2]/text()"));

New Table("Sigma GRR",

       new column("Estimates", Character, SetValues(est)),

       new column("LCI", Character, SetValues(LCI)),

       new column("UCI", Character, SetValues(UCI)),

      

);

Kevin_Anderson

Hi, Vince!

Not sure this is what you're after, since there are many, many ways to do this, but you could always "roll your own"...

Names Default to Here(1);

// Open the dataset in question.

BigClass_dt = Open( "$SAMPLE_DATA/Big Class.jmp" );

// Summarize the standard deviation by age.

BigClassSummary_dt = BigClass_dt << Summary(

  Group( :age ),

  Std Dev( :height ),

  output table name("Big Class Summary"));

// Set alpha as a table variable.

BigClassSummary_dt << Set Table Variable("alpha", 0.10);

// Calculate the Confidence Intervals

BigClassSummary_dt << New Column( "LCI",

  numeric, continuous,

  Formula( Root(((:N Rows - 1) * :Name( "Std Dev(height)" ) ^ 2) / ChiSquare Quantile( 1 - :alpha / 2, :N Rows - 1 ), 2 )),

  eval Formula);

BigClassSummary_dt << New Column( "UCI",

  numeric, continuous,

  Formula( Root( ((:N Rows - 1) * :Name( "Std Dev(height)" ) ^ 2) / ChiSquare Quantile( :alpha / 2, :N Rows - 1 ), 2 ) ),

  eval Formula);

// Revel in your fly statistical swerve!