<Li> Increase in income if good is inferior good </Li> <P> There is movement along a demand curve when a change in price causes the quantity demanded to change . It is important to distinguish between movement along a demand curve, and a shift in a demand curve . Movements along a demand curve happen only when the price of the good changes . When a non-price determinant of demand changes the curve shifts . These "other variables" are part of the demand function . They are "merely lumped into intercept term of a simple linear demand function ." Thus a change in a non-price determinant of demand is reflected in a change in the x-intercept causing the curve to shift along the x axis . </P> <P> If a commodity is sold in whole units, and these are valuable for a consumer, then the individual demand curve can hardly be approximated by a continuous curve . It is a set function of the price, defined by a price above which no unit is bought, a price range for which one is bought, etc . </P> <P> If the local currency is dollars, for example, then the units of measurement of the variable "price" are "dollars per unit of the good" and the units of measurement of "quantity" are "units of the good per time (e.g., per week or per year). Thus quantity demanded is a flow variable . </P>

Which of the following is not a shifter of the demand curve