Custom Calculation Script - Standard Deviation

[michelled19159583]

I am having trouble creating a Custom calculation script in my Adobe Acrobat XI Standard. I have a table with fields row_1, row_2, row_3, row_4, row_5, row_6, row_7, row_8, row_9, row_10, row_11, row_12, row_13, row_14, row_15. I have a field that already calculates the mean, that field name is mean. So far I have been able to create this but it does not work:

sqrt(((((row_1-mean)^2)+((row_2-mean)^2)+((row_3-mean)^2)+((row_4-mean)^2)+((row_5-mean)^2)+((row_6-mean)^2)+((row_7-mean)^2)+((row_8-mean)^2)+((row_9-mean)^2)+((row_10-mean)^2)+((row_11-mean)^2)+((row_12-mean)^2)+((row_13-mean)^2)+((row_14-mean)^2)+((row_15-mean)^2)))/15)

[Bernd Alheit]

You must change your code.

E.g. you will get value of field row_1 with:

this.getField("row_1").value

[michelled19159583]

What must I change it to? I am stuck. row_1, row_2, etc. are imputed values that the user manually enters. My issue is I need to find an equation that will work in Adobe Acrobat that finds standard deviation of a set of numbers. Do you know how to do this?

[try67]

And here you can learn how to perform basic mathematical operations (like square root and power) in JS: JavaScript Math Object

[michelled19159583]

My issue isn't writing the actually code. I just cannot seem to get any of them to actually work within Adobe Acrobat. For example, if I want the Standard Deviation of the field name mean. Example: stdev(mean). This will not work in the Custom calculation script. Can you please help me. am I missing something in front of the code?

[try67]

Why would it work? Did you create a function called stdev? There's no such function built-in to JavaScript or Acrobat, so there's no reason to assume it will magically work...

[michelled19159583]

Currently it works! I am not sure what you mean! stdev() is a standard JavaScript function.

[try67]

AFAIK, it's not. Show me where it's documented...

[michelled19159583]

Right now this is working separately.

In one form field(Simplified field notation) named MEAN_2 I have:

((((row_1-mean)*(row_1-mean))+((row_2-mean)*(row_2-mean))+((row_3-mean)*(row_3-mean))+((row_4-mean)*(row_4-mean))+((row_5-mean)*(row_5-mean))+((row_6-mean)*(row_6-mean))+((row_7-mean)*(row_7-mean))+((row_8-mean)*(row_8-mean))+((row_9-mean)*(row_9-mean))+((row_10-mean)*(row_10-mean))+((row_11-mean)*(row_11-mean))+((row_12-mean)*(row_12-mean))+((row_13-mean)*(row_13-mean))+((row_14-mean)*(row_14-mean))+((row_15-mean)*(row_15-mean)))/15)

In another form field(Custom calculation script) I have:

event.value = Math.sqrt(this.getField("MEAN_2").value) ;

The second one correctly outputs the Standard deviation of the mean. But, I would like to not have two form fields. All I need is the standard deviation of the form field mean. But for some reason stdev(mean) wont work.

[Bernd Alheit]

In the simplified field notation you can only use the operators + - * /

You must change the whole code to JavaScript.

[michelled19159583]

Hi Bernd. Do you have any idea of how I could change the entire thing to JavaScript?

So far, I have a "Value is the average" in one form field which creates the mean, this form field is labeled 'mean'. In the next form field I have a "Simplified field notation" : ((((row_1-mean)*(row_1-mean))+((row_2-mean)*(row_2-mean))+((row_3-mean)*(row_3-mean))+((row_4-mean)*(row_4-mean))+((row_5-mean)*(row_5-mean))+((row_6-mean)*(row_6-mean))+((row_7-mean)*(row_7-mean))+((row_8-mean)*(row_8-mean))+((row_9-mean)*(row_9-mean))+((row_10-mean)*(row_10-mean))+((row_11-mean)*(row_11-mean))+((row_12-mean)*(row_12-mean))+((row_13-mean)*(row_13-mean))+((row_14-mean)*(row_14-mean))+((row_15-mean)*(row_15-mean)))/15). This is part of the equation to find the standard deviation, this second form field is labeled 'MEAN_2'. In the third and final form field I created a "Custom calculation script" : event.value = Math.sqrt(this.getField("MEAN_2").value) ;. That last script takes the square root of the form field MEAN_2, thus giving me the standard deviation. Any idea of how I can combine them all into one?

[Bernd Alheit]

One sample for standard deviation:

Java script for standard deviation (JavaScript)

[michelled19159583]

Bernd-

This is what I have come up with thus far:

var MyValues = new Array();

var MyFields = new Array("row_1", "row_2", "row_3", "row_4", "row_5");

var oField;

var nField;

for(var i = 0; i < MyFields.length; i++)

{

  nField = '';

  nField = GetField(this, MyFields).valueAsString;

  if(nField != "") MyValues.push(Number(nField));

}

event.value = standardDeviation(MyValues);

Any help is much appreciated.

Thanks,

Michelle

[michelled19159583]

Bernd-

I found this. But it doesn't work right now. Am I listing the row_'s wrong? Do I have to add something before I list them?

var average = this.getField("mean").value;
var v = 0;
var fieldName = "row_1, row_2, row_3, row_4, row_5, row_6, row_7, row_8, row_9, row_10, row_11, row_12, row_13, row_14, row_15"; 
var s = 0;
var sd = 0;
n = 15; //number of fields

for (var i = 1; i < n+1; i++) {
    v = this.getField(fieldName + i).value;
    s = s + Math.pow((v - average), 2);
}

sd = Math.sqrt(s / n); //standar deviation
event.value = sd;

Thanks,

Michelle

[michelled19159583]

This won't work either:

var average = this.getField("mean").value;
var v = 0;
var fieldNames = new Array("row_1", "row_2", "row_3", "row_4", "row_5", "row_6", "row_7", "row_8", "row_9", "row_10", "row_11", "row_12", "row_13", "row_14", "row_15"); 
var s = 0;
var sd = 0;
n = 15; //number of fields

for (var i = 1; i < n+1; i++) {
    v = this.getField(fieldNames + i).value;
    s = s + Math.pow((v - average), 2);
}

sd = Math.sqrt(s / n); //standar deviation
event.value = sd;

[Bernd Alheit]

Look at the sample. It doesn't use an array. You must use:

var fieldName = "row_";

[michelled19159583]

Hi Bernd,

It doesn't work with just var fieldname="row_";

var average = this.getField("mean").value;
var v = 0;
var fieldName = "row_";
var s = 0;
var sd = 0;
n = 15; //number of fields

for (var i = 1; i < n+1; i++) {
    v = this.getField(fieldNames + i).value;
    s = s + Math.pow((v - average), 2);
}

sd = Math.sqrt(s / n); //standar deviation
event.value = sd;

[michelled19159583]

This doesn't work either:

var average = this.getField("mean").value;
var v = 0;
var fieldName = ("row_1", "row_2", "row_3", "row_4", "row_5", "row_6", "row_7", "row_8", "row_9", "row_10", "row_11", "row_12", "row_13", "row_14", "row_15");
var s = 0;
var sd = 0;
n = 15; //number of fields

for (var i = 1; i < n+1; i++) {
    v = this.getField(fieldNames + i).value;
    s = s + Math.pow((v - average), 2);
}

sd = Math.sqrt(s / n); //standar deviation
event.value = sd;

[gkaiseril]

Open Acrobat's JavaScript Console and see if there are any errors.

You use the <Ctrl/Options> +"J" key combination.

It appears line 9 of the script is trying to access a field that does not exist.

You need to make a couple of changes. Fix the name of the array and fix the index value for walking the array's elements.

Try:

var average = this.getField("mean").value;
var v = 0;
var fieldName = new Array("row_1", "row_2", "row_3", "row_4", "row_5", "row_6", "row_7", "row_8", "row_9", "row_10", "row_11", "row_12", "row_13", "row_14", "row_15");
var s = 0;
var sd = 0;
n = 15; //number of fields

for (var i = 0; i < n; i++) {
    v = this.getField(fieldName).value;
    s = s + Math.pow((v - average), 2);
}

sd = Math.sqrt(s / n); //standar deviation
event.value = sd;

If your values are small and there is very little variation, it is possible that your standard deviation maybe close to zero and the calculation will result in a value expressed in scientific notation which for a field formatted as a number will throw an error about value not matching the field's format.

[michelled19159583]

gkaiseril -

You are amazing!!! It works, thanks so much.

[michelled19159583]

Update:

This is the current script I have and it works properly to calculate the Population Standard Deviation:

var average = this.getField("mean").value;
var v = 0;
var fieldName = new Array("row_1", "row_2", "row_3", "row_4", "row_5", "row_6", "row_7", "row_8", "row_9", "row_10", "row_11", "row_12", "row_13", "row_14", "row_15");
var s = 0;
var sd = 0;
n = 15; //number of fields

for (var i = 0; i < n; i++) {
    v = this.getField(fieldName).value;
    s = s + Math.pow((v - average), 2);
}

sd = Math.sqrt(s / n); //standar deviation
event.value = sd;

However, I need the Sample Standard Deviation. Can anyone help me?

Thanks,

Michelle

[Bernd Alheit]

sd = Math.sqrt(s / (n - 1));

[gkaiseril]

Instead of dividing by the population n one divides by the sample n - 1.