I have data that I have collected suggests that the prices are more or less constant throughout the month whereas the quantity demanded changes on a day to day basis. Recalling the formula for PED, we can write:
$$PED= {P*\Delta Q \over Q*\Delta P}$$ we can observe that $\Delta P=0$ as I mentioned earlier, giving us $PED=infinity$. However in reality the demand is inelastic. Is there a way to handle this error?
Assumption while measuring the prices: The supply was constant.
These are tuples of the form (Price and Demand)
(275,30)
(275,80)
(275,20)
(275,70)
(282,0)
(282,50)
(282,100)
(282,80)