Tuesday, May 28, 2013

SBAC Part 2 - The Questions.

Random observations:
  • The pilot high school test we took did not include trig, logs, complex numbers, and many geometrical standards.
  • No offense to the writers but I found a sick love of completing the square, parabolas, throwing balls, difficult factoring, multiplying many many terms, geometric proofs, and simplifying unnecessary fractions.  
  • The difficulty level was extremely high, out of 60 to 74 questions, I'd say there were less than 5 questions that were straight forward and did not have multiple parts.
  • There is no way any student could legitimately get through the test in two hours.
  • The calculator was only allowed on certain problems.
  • After 15 questions, it saved the work and students could not go back to those questions.
  • Unclear directions: Should students simplify completely?   Write the abbreviation for units?
  • Questions ran off the screen, which drove students nuts. 
Let's look at one of the problems from the teaser.


There's nothing wrong with this problem, except it's way too complex for most students.  I believe this is an example of an "easy" problem.  Thanks to SBG (Standards Based Grading), I know that this is an extremely difficult problem for students.

Here's the breakdown: for (x + 3)^2 = 16:  84% of students get this correct.
                                     for 2(x +3)^2 = 32:  51% of students get this correct. 37% get both solutions
                                     for 2(x+3)^2 + 7 = 39: 36% of student get this correct. 22% get both solutions.

The scoring for this would be interesting.  Do they get full credit for one of the two solutions?  What if they left the answer in radical form or x = –3 +/- 4?  What if they write x = 1 AND x = –7 instead of x = 1 OR x = –7, or x =1, –7?  I'm sure we'll never know how they scored this problem (unless we pay for it).

I believe if you want to know if students can solve from the vertex form a quadratic the problem (x + 3)^2 = 16 would be a better choice.  Perhaps, a better way to assess solving quadratics would be a problem like x^2 + 10 = 19, where they could factor it or isolate x.

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