How do I determine PED from price consumption curve with slope of zero?
Since you have discrete datapoints and want to calculate PED, you will have to make assumptions, like &quot;the data represents the general behavior of the consumption function&quot;. (You can also get more data or throw your hands up in despair.)
If you know that price has no effect on the quantity demanded, you can apply the PED formula, and get a very specific number for PED.