A graphical tool used in economics to analyze the long run choice of factors of production is the isocost/isoquant analysis. A graphical tool used in economics to analyze the long run choice of factors of production is the isocost/isoquant analysis.

There was a gradual decline in sales. Sales declined gradually (noun usage) (verb usage) Enrollment increased by 4% in 1997. There was a 4% increase in enrollment in 1997. Immigration rose to 800,000 in 1999. Immigration rose by 20,000 in 1999. (to a point/number) (by increment) There was a 20% rise in immigration. (percentage)

Income expansion path -IEP- traces all the best (utility-maximizing) choices a consumer makes as income changes. The IEP slopes up if a good is a normal good The IEP is downward sloping if a good is inferior An Engel curve plots all the best choices a consumer makes against INCOME. It is an income-quantity relationship If an Engel curve is upward sloping, a good is normal; downward sloping indicates an inferior good.