In the frame below is a scatterplot of some 1990 US Census data population and housing. The variables, reported for each of the 50 states and the District of Columbia, are: Abbreviations of Census variables Variable Abbreviation population in thousands persons/1000 I total housing units per 1000 people housing units/1000 occupied rentals per 1000 people occupied rentals/1000' vacant housing units per people vacancies/1000 vacant rental units per 1000 people vacant rentals/1000 median rent in dollars median rent($) Data: housing- 1990.son vacancies/1000 VS median rent($) 290 - 280 270 260 250 240 230 220 210 200 190 180 170 160 200 250 300 350 150 500 550 600