about standard deviation

Please Dear..

i have used adobe livecycle designer Es2 for making form, i want to calculate the standard deviation for 5 feilds named (F1,F2,F3,F4,F5) which is numeric and i think that this can be done through a custom calculating script.. can you help me please in a code to perform this calculation... the previous was in adobe acrobat pro but when use the same code it does not work with adobe livecycle designer.. please help me in this issue

thsi was the code that i use in adobe acrobat pro:

var MyValues = new Array();

var MyFields = new Array("F1", "F2", "F3", "F4", "F5");

var oField;

var nField;

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

{

  nField = '';

  nField = GetField(this, MyFields[i]).valueAsString;

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

}

event.value = standardDeviation(MyValues);

so i need code perform the same function for adobe livecycle designer

thank you