ECO - Determine the Price-Elasticity of Demand Coefficient

Column I - determine the Price-Elasticity of Demand Coefficient. Refer to the Price-Elasticity
Coefficient and Formula :
change in quantity demanded
EP = ---------------------------------------sum of quantities demanded / 2 change in price

∕ ---------------------------sum of prices / 2

The data in the first four columns represent price (P) and quantity demanded (Qd) in time 1 (before change in price) and time 2 (after change in price) for a specific good. Note that results should be expressed in absolute terms. For example, -1 should be expressed as │1│, as should a positive 1.
Column II – Interpret the results and indicate the type of elasticity which applies (such as Elastic, Inelastic, Perfectly Elastic, Perfectly Inelastic, Unitary) based on how the quantity demanded changed subsequent to a change in price.
Column III – Determine if the good in question would be considered a necessity, a luxury or neither.
Column IV – Indicate, in monetary terms, how much is the change in total revenue or total expenditure (TR = P X QD), from the first price level to the second.
Column V - indicate the direction of the change, that is, increasing or decreasing (show a + sign for increasing and a – sign for decreasing).
Note: for any monetary result please include the applicable currency symbol ($, €, etc.)