[ColoradoTree]

Regarding the smaller percentages of students in the Upper Midwest taking the SAT, I would place less emphasis on the availability of agricultural jobs and more on the fact that more students in that part of the country take the ACT instead. 

As to why, I'm not entirely sure.  But I do know that there has long been a geographical bias in favor of the ACT in the Upper Midwest.  See, e.g., http://www.nytimes.com/2007/11/04/educat...nted=all.  When I was graduating from a Minnesota high school in 1999, this was still very much the case.  Everyone I knew took the ACT, and a much smaller percentage took the SAT.  While Minnesota colleges accept both the ACT and SAT (as far as I know), there was a perception among students that Minnesota colleges preferred the ACT because of a greater familiarity with the test, and some students believed that local schools required the ACT but not the SAT.  (I don't know if that was true then or is true now, but it was a widely-held belief.) 

According to this study (http://www.people.vcu.edu/~mamcdani/Publ...buttal.pdf), just 11% of Minnesota high school graduates in 2005 took the SAT, but 66% took the SAT.  The disparity is more pronounced in some other states.  For example, Mississippi had 94% of graduating seniors take the ACT, while just 4% took the SAT.  On the other hand, New Jersey's split was 86/6 the other way. 

[ColoradoTree]

Regarding the smaller percentages of students in the Upper Midwest taking the SAT, I would place less emphasis on the availability of agricultural jobs and more on the fact that more students in that part of the country take the ACT instead. 

As to why, I'm not entirely sure.  But I do know that there has long been a geographical bias in favor of the ACT in the Upper Midwest.  See, e.g., http://www.nytimes.com/2007/11/04/educat...nted=all.  When I was graduating from a Minnesota high school in 1999, this was still very much the case.  Everyone I knew took the ACT, and a much smaller percentage took the SAT.  While Minnesota colleges accept both the ACT and SAT (as far as I know), there was a perception among students that Minnesota colleges preferred the ACT because of a greater familiarity with the test, and some students believed that local schools required the ACT but not the SAT.  (I don't know if that was true then or is true now, but it was a widely-held belief.) 

According to this study (http://www.people.vcu.edu/~mamcdani/Publ...buttal.pdf), just 11% of Minnesota high school graduates in 2005 took the SAT, but 66% took the SAT.  The disparity is more pronounced in some other states.  For example, Mississippi had 94% of graduating seniors take the ACT, while just 4% took the SAT.  On the other hand, New Jersey's split was 86/6 the other way.