Tall, Dark, and Mysterious

4/21/2005

Exam notes: qualitative

File under: 1000 Words, Those Who Can't. Posted by Moebius Stripper at 3:46 pm.
  1. Despite the fact that marks-wise, I was most disappointed by the statistics students (several of them can’t plug numbers into their calculators! I gave them a formula sheet! They copied the correct formula down correctly! Wrote down the correct numbers for the variables! And got the wrong result!), their papers were the most enjoyable to grade, because the statistics students tended far moreso than the students in my other classes to leave me little notes about how they felt about the material. For instance, I had a probability question about a die-rolling game, which one girl opted to inform me was the “stupidest game EVER.” Another student (correctly) subjected a manufacturer’s claim about its products to statistical analysis before stating her conclusion, as instructed, “in [her] own words”: “It’s TOTAL BS!” Also, my attempt to make mathematics relevant to the lives of my students succeeded in the mind of one student: I included a question in which students were to test a hypothethesis that women generally underreport their weights, which prompted one pupil to write sic, “OMG THIS IS SO TRUE, I DO THIS ALL THE TIME.” (She did the question incorrectly.)

  2. Aside to all students reading this: if you are ever asked to define a term on a test, and you don’t remember what that term means in the subject - for instance, math - that the test is about, try analyzing the language in the term. I mention this because hardly any of my students were able to tell me what mutually exclusive events were (most gave me the definition of independent events), even though realizing that “exclusive” and “exclude” contain the same root just might be enough to jog the memory. The only student to attempt a linguistic desconstruction was an Asian girl whose English is shaky. “Mutually exclusive events,” she wrote, “are events which are very special…”

  3. Back to the die-rolling game: when my contract expires at the end of the month and I am without regular income, would it be unethical to engage some of my former students in various games for money? I have certain students in mind, such as the guy who wrote that if you play one hundred rounds of the game that costs you $4 per round and that pays you the dollar value of the number appearing on the top face of the die, then you can expect to make $2000.

  4. The college where I work prides itself as being “student-centred”. Part of what this means is that the many, many student lounges are located “centrally”, like right outside classrooms and adjacent to them. I submit that if there was ever a good reason to revoke an architecture degree, then surely this design is it. Precalculus was held in a lounge-adjacent room, as was the statistics exam. During both, students were in the lounge, chatting at perfectly normal volumes, which was enough to create a distraction for me and my students. On approximately fifty occasions this term, I had to enter the lounge to request quiet, because a dozen students talking quietly results in a din that is not quiet. On forty-eight of these occasions, students were apologetic and lowered their voices accordingly, which helped things for the next twenty minutes until either a) they got excited about something else, or b) they were replaced by an uninitiated group of students. (Large signs in the lounge requesting quiet do not help.)

    The other two times, I had the pleasure of dealing with one girl who asserted her rights to sit at the lounge and talk because “this is the only place where we can do this”, where (judging from the lack of books or anything else on the table where she and her friends were sitting) “this” consisted of sitting and talking with two friends in the lounge outside my classroom. She told me that this was “total bullshit” and that “maybe I should use a different classroom”, as though it was my decision to teach and hold exams in a room that is a ten minute walk from my office and is located right next to a student meeting hub that has the acoustics of a cathedral. When I quietly explained that although perhaps the lounge was the only place where she could do “this”, it was even more certain that the adjacent classroom was actually the only place where my students could write their exam for the next twenty-five minutes, she declared that this was TOTAL BULLSHIT. WE ARE TALKING AT A NORMAL VOLUME, which at that point was no longer true. Grasping for common ground, I started to tell her that I was in agreement with the bullshit assessment, and reached into my pocket to call campus security on my cell phone when her friend - bless his heart - said, “Come on, we can go somewhere else for the next half hour…there’s an exam, she’s asking us nicely.” And that, apart from an evil eye directed my way (me without my camera, I tell you), was the end of that.

  5. Often I get teaching advice from my readers. I should do dimensional analysis! I should make math relevant to their lives! I should relate the difficult concepts they’re studying now to the easy concepts they’re familiar with!

    Generally I smile and nod, because I think that few of my readers know what I’m dealing with. Allow me, then, to present an example of what I am dealing with:

    The question, which is a bit unclear in the image, reads “Solve for x: 4x+2(1/2)-2x = 8x+2.” The student’s work, which follows, resembles the sort of thing junkies might hallucinate if LSD induced images of equations. Notice how the variable x goes missing in the very first line of this “solution”, leaving an equation that reduces to 0=0, which is then tortured until it finally gives up the ghost - though not before confessing, in its dying breath, that x (remember x? it’s back!) equals 50. Note also how the declaration that we “can’t have negative numbers” (surely a surprise to those of us who have endured frigid Canadian winters during which the temperature dipped to…oh, CRAP) apparently allows us to do away with them altogether, on our own terms, and at our leisure. (Ernie has taken the time to transcribe this work of art, in toto.)

    No, this corruption of reason is not representative of a typical paper in my precalculus class. However, it is representative of a typical page of this student’s exam (she got a 3% on it, and this was with me assigning marks to everything that even vaguely resembled mathematics - by the way, she sat in the exam room for an hour and a bloody HALF tormenting her paper; I left out the question in which she concluded that a $1000 principal invested at 4.8% per year compounded continuously yields $240,000 after five years, and I also left out around ten others that I could easily have posted instead of the one above), and I have had, on average, two students like her in every class I have taught in the past five years. I guess I could have spent more time on dimensional analysis and such, but somehow I don’t think it would have helped that much.

    (ETA: By popular request (okay, one person asked, but apparently he speaks for all), here’s more of the exam.)

  6. One of my students missed an exam because of a dire family situation, which now requires me to navigate that murky territory between being sympathetic and being a sucker. I don’t want to get into too much detail, but suffice it to say that Distressed Student is both suffering a terrible crisis, and attempting to play the system like it’s going out of style. I’ve had to outline explicitly what I am and am not willing to do to accommodate her. For example: I am willing to allow her to write the exam a month from now, but I am not willing to just assign her a final grade that assumes that her exam grade would have surpassed the class average by nearly 10% when her term test grades consistently fell far short of it. As evidence that this student’s family crisis is not the only thing standing between her and such success on the final exam, I present the email she sent me the other day, which read, in part, Since I am going thru such difficulties would you be able to just make my term mark my final grade? Right now I have 41/65 on the quizzes and tests. I have been meeting with a math tutor for the past few weeks and he told me that this is a 63%, which is the mark I need in this course.

Exam notes: quantitative

File under: Those Who Can't. Posted by Moebius Stripper at 1:26 pm.
  1. Number of pages of exams graded in the past six (6) days: 1344

    • For precalculus: 392
    • For calculus: 280
    • For statistics: 644
  2. Average number of unclaimed tests/quizzes sitting in my office, per student, in
    • Precalculus: 2.7
    • Statistics: 1.1
    • Calculus: 0.5
  3. Number of students enrolled who didn’t show up for the final exam: 5
    • Of those, number who have dealt with situation quickly and painlessly: 2
    • Number who are being ongoing big pains in the ass to deal with: 1
    • Number who have said nothing and who, judging from their term marks, can safely be assumed to have dropped the course, in spirit if not in writing: 2
  4. (Inspired by Becky) Pearson’s correlation coefficient relating position of statistics student’s surname in alphabet (46 students wrote the exam) with student’s exam grade: 0.466.
    • Probability that the correlation in a simple random sample of size 46 would be so strong if there were, in general, no correlation between surname and exam grade: less than 1%
    • Regression equation relating student’s grade y to first initial of student’s surname x: y=52+0.94x
      • Predicted grade for Aaron Aaronson: 53%
      • Predicted grade for Ziggy Zuckerman: 76%
    • First initial of Needs-a-B’s surname: B
    • Actual exam grade of Needs-a-B: Less than 50%
    • Number of mistakes on Needs-a-B’s exam that were identical to ones she’d made several times before, on quizzes or tests, and that I’d addressed explicitly with her during my office hours: 4