BOSTON (

TheStreet

) -- Minnesota residents are at the top of the class when it comes to educational achievement -- but South Carolinians get an "F," we have found.

A look at four educational factors -- average SAT math scores, percentage of citizens with high-school diplomas, how many young people attend college and how many high schoolers watch too much TV -- reveals wide variations among U.S. states.

For instance, just 8.2% of residents in first-place Minnesota lack high-school educations -- roughly half of the 15.9% rate in last-place South Carolina. Similarly, 80.4% of Minnesota's 18- to 24-year-olds are enrolled in college, compared with just 49.9% of similarly aged South Carolinians.

Boston College education professor Ana Martinez-Aleman attributes much of the variations to a single factor -- how much money states spend on public schools.

"There's a cause-and-effect relationship between school funding and educational achievement," says Martinez-Aleman, who also serves as editor of the scholarly publication

Educational Policy Journal

. The expert says some states have long showered their secondary-school and public-university systems with big bucks, while others have made funding about as hard to come by as an "A" in calculus.

"Public-school funding is primarily derived from property taxes, and

state and local governments determine property-tax rates," she says. "The lower your revenue stream, the lower your ability to fund education."

Martinez-Aleman adds that she's not surprised that all five states that ranked worst on the analysis are in the deep South, a region she says has historically had lower taxes and less educational spending. The professor also believes the South's poor showing partly stems from a legacy of past discrimination against minorities.

She thinks decisions made during segregation still result in inadequate funding for schools with lots of black and Hispanic students, setting many young people up for lower educational achievement.

"A school that's poorly funded tends to have fewer experienced teachers, fewer advanced courses, fewer extracurricular activities and fewer services like college counseling," Martinez-Aleman says. "So the

students are handicapped."

Here's a look at the five states at the bottom of our analysis of educational achievement, which we compiled using the most-recent data available from The College Board and

Educational Policy Journal

's sister company,

CQ Press

.

States are ranked based on an average of where they placed among all 50 states and the District of Columbia on all four metrics analyzed. (Nine states and D.C. lacked data on TV watching by high schoolers, so we ranked them based on their average scores for the three other criteria studied.)

All Scholastic Aptitude Test math scores are from this year, while the percentage of students taking the SAT is based on average figures calculated by The College Board for 2002, 2011 and 2012.

Percentage figures for people in each state lacking high-school or general-equivalency degrees are as of 2010 and refer to residents 25 or older, while college-enrollment rates for each state's young people are as of 2008. Television-watching statistics are as of 2009:

Fifth-dumbest state in America: Mississippi

The Magnolia State comes in virtually last place in two of the four factors we analyzed -- how many residents over 25 lack high-school educations and how many high-school students watch tons of TV.

Research shows that 44.9% of Mississippi high schoolers spend three hours a day or more in front of the boob tube -- the worst ranking of any state measured.

Similarly, the 19% of adult Mississippians who lack high-school degrees represent the second-highest rate nationally, besting only Texas and California (which tied for last place).

The Magnolia State also ranks ninth-worst for young people attending college, with just 52.7% of 18- to 24-year-olds enrolled in high education.

In fact, Mississippi's only bright spot among the factors we analyzed was its average SAT math scores. Students got a 544 mean score on the test in 2012 out of a possible 800 -- the 15th-best showing nationwide.

Just 4% of Mississippi students generally take the SAT, though -- a low showing that can skew results. The College Board, which oversees the test, says low participation rates usually mean only the best students take the SAT, artificially inflating a state's average score.

Fourth-dumbest state in America: Louisiana

Louisiana's educational performance is no cause for a Mardi Gras parade.

The Bayou State ties Kentucky for the third-highest proportion of adults without high-school degrees (18.1%), and has the sixth-lowest percentage of 18- to 24-year-olds enrolled in college (50.4%).

And when it comes to television viewing, the 40.3% of Louisiana high schoolers who spend three hours or more a day watching TV trail only their Mississippi counterparts as the nation's highest ratio of budding couch potatoes.

On the other hand, Louisiana's 536 average SAT math score does tie Montana for 17th place nationwide. But only 9% of Louisiana students typically take the test -- and as noted previously, low participation rates can skew a state's average upward.

Third-dumbest state in America: Texas

The Lone Star State stands virtually alone when it comes to the proportion of an area's citizens who didn't finish high school.

Texas ties California for dead last among the 50 states and the District of Columbia in terms of residents 25 or older without high-school educations -- 19.3% for both states.

The Lone Star State also places 10th from the bottom in terms of young people attending college, with just 52.8% of 18- to 24-year-olds enrolled in post-secondary schools.

Similarly, a 499 average SAT math score places Texas at a below-average 28th place nationwide, while 36.3% of the state's high schoolers watch three hours or more of TV daily. That's the 11th-highest rate nationwide.

Second-dumbest state in America: Georgia

Honey Boo Boo's home state falls in the bottom quartile of performance in all four measures analyzed.

Georgia gets particularly low grades in two areas we studied: TV watching among high-school students and the percentage of young residents attending college.

Just 50.2% of 18- to 24-year-old Georgians are enrolled in higher-education institutions, the fifth-lowest proportion for any state or the District of Columbia.

Similarly, Georgia places fourth-worst for TV viewing by students, with 39.2% of high schoolers spending three or more hours a day in front of the idiot box.

The Peach State's students also averaged just 489 on the SAT math test, placing them fifth from the bottom nationwide.

Finally, 15.7% of Georgians 25 or older lack high-school educations -- the 11th-highest ratio nationally.

Dumbest state in America: South Carolina

The Palmetto State finds itself at the bottom of the heap due to near-last-place results in all four measures we studied.

South Carolina did especially poorly in the area of television watching by high schoolers, with 39.7% of students watching at least three hours of TV per day. Only Louisiana and Mississippi rate worse.

Similarly, the state comes in nearly last place in the percentage of young people enrolled in college. Just 49.9% of 18- to 24-year-old South Carolinians attend institutions of higher learning -- a level so low only Montana, Nevada and Alaska trail it.

The state also places near last nationwide in terms of SAT math scores. South Carolina students scored 488 on average in 2012, the fourth-lowest showing among all 50 states and the District of Columbia.

Lastly, 15.9% of South Carolinians never graduated high school -- the 10th-worst rate nationwide.