Script to duplicate Basic Paragraph style, then change character point size

Question

I'm looking to create a script that will create a cascade of paragraph styles based on the [Basic Paragraph] style settings. My goal is for each new paragraph style's character point size to be a percentage of the original [Basic Paragraph]'s. So if [Basic Paragraph] is 100% (character point size 10pt), the script would create a paragraph style named '120%' that has a character point size of 12pt. Then 133%, 140%, so on and on. I modified a script found on this forum to generate those new styles, but I don't know how to create them to be basedOn the [Basic Paragraph]. Any help would be very much appreciated, thanks in advance.
current script:
var doc = app.activeDocument,  
    pstyle = ["100%", "120%", "133%" ];  
for(var i =0;i<pstyle.length;i++)  
        if(pstyle[i] == "100%") 
            doc.paragraphStyles.add({name:pstyle[i], appliedFont:"Stag", pointSize:10});              
        else if(pstyle[i] == "120%") 
            doc.paragraphStyles.add({name:pstyle[i], appliedFont:"Stag", pointSize:10*1.2})              
        else if(pstyle[i] == "133%") 
            doc.paragraphStyles.add({name:pstyle[i], appliedFont:"Stag", pointSize:10*1.33333})              

Answer 1

Try this,
var doc = app.activeDocument, 
    pstyle = ["100%", "120%", "133%" ]; 
for(var i =0;i<pstyle.length;i++) 
        if(pstyle[i] == "100%")
            doc.paragraphStyles.add({name:pstyle[i], basedOn: doc.paragraphStyles[1], appliedFont:"Minion Pro", pointSize:10});             
        else if(pstyle[i] == "120%")
            doc.paragraphStyles.add({name:pstyle[i], basedOn: doc.paragraphStyles[1], appliedFont:"Minion Pro", pointSize:10*12})             
        else if(pstyle[i] == "133%")
            doc.paragraphStyles.add({name:pstyle[i], basedOn: doc.paragraphStyles[1], appliedFont:"Minion Pro", pointSize:10*1.33333})             
Vandy