4 ms·

If this was such common knowledge amongst his students at UCF, then why was this the first time that the professor saw the bimodal distribution in the test scor

If this was such common knowledge amongst his students at UCF, then why was this the first time that the professor saw the bimodal distribution in the test scores? Why didn't his Summer class's test scores have the same distribution? I think a lot of the comments in this thread are making assumptions about what the students did or didn't do, and might possibly be excusing some unethical behavior because of faulty assumptions.

thisisnotmyname 16y ago
As someone who works with data I can tell you that distributions can take on all kinds of unexpected shapes, especially when n=600. I think he's bluffing - the stats can't prove that anyone has cheated. That said, the deal he offered sounded pretty good when compared to the alternative.
- paulgb 16y ago
  My thoughts exactly. If I were a non-cheating student in that class, I would be very tempted to confess anyway, out of fear that I would be a victim of the prof's over-confidence in his statistical analysis. He mentioned being able to supply the dean with a list of people with 95% confidence that everyone who cheated was on the list, with no apparent concern for any false positives. The confession offer is pretty good in comparison.
  - homonculus 16y ago
    "He mentioned being able to supply the dean with a list of people with 95% confidence that everyone who cheated was on the list, with no apparent concern for any false positives." Right after that, he said that he couldn't be sure everyone on the list had cheated. He is saying that he thinks every cheater is on the list, but not everyone on the list is a cheater.
    - paulgb 16y ago
      Right, that's not too impressive though, the class register would have everyone who cheated on it with 100% confidence.
- sequoia 16y ago
  I, as a non-statistician, agree that he was bluffing. If I were a student in that class with a high grade, cheating or no (because even the innocent may get accused and face the ostensibly severe consequences), I would be thinking "Hmm... Now how exactly does he plan on proving that I cheated?" Without a confession or third party who could reliably state that they know hypothetical-I was cheating, the possibility of actually proving misconduct on an individual level seems extremely remote. I would love to hear some statistics folks weigh in on this. Or: speculation ftw!
- runningdogx 16y ago
  That assumes that proof of anything is required. That's not usually how college disciplinary actions work. At its worst, universities will sometimes assume a student accused of wrongdoing is lying, and punish the student based solely on the word of the faculty/staff bringing the charge. This happens in lesser cases where the administration thinks it can get away with it, and when the student is frightened of harsher sanctions that might be inflicted if the student asserts his or her rights and demands a full hearing process. At its best (typically in more serious cases), the disciplinary process resembles a civil case (except instead of a jury, it's more of a tribunal) where the required proof is a preponderance of the evidence. It's no wonder 200 students confessed. If I was in that class and I'd never seen the test bank, I'd have confessed too. It's been my observation that the disciplinary process is better at railroading not-provably-guilty students than punishing provably-guilty students. I would not want to take my chances.
gojomo 16y ago
Perhaps this was the first semester that what had been known to a few people, or whispered about, became widely known. Perhaps this was the first time a digitized copy of the test bank got widely distributed -- maybe even because the publisher's standards for selling the test bank got loosened. At a smaller but growing scale, over several semesters, this tactic of using the test bank might not lead to any striking anomalies in the distribution... just a gradual rise in the average, and fattening of the above-the-median tail. For a while, that might convince the professor he's doing better! (Also, while we see Summer scores for comparison, he doesn't show the prior Spring or Fall. Often Summer students are a different pool, who in this case may not have been privy to the same campus folklore. Perhaps there was evidence of the same tactic earlier, or another professor with a different exam style taught previously.) Lots of speculation, I know, and I would need more information to assign levels of culpability overall. Were students specifically warned off using test bank questions? Did those who obtained the questions lie to the publisher to acquire them? How similar were the circulated test bank questions to other official preparation materials? Etc. It could also be interesting to see, on the makeup exam with presumably all-new but similarly-difficult questions, has the average mastery gone up? Perhaps memorizing the test bank questions does have some persistent beneficial effect for understanding the material.

thisisnotmyname 16y ago

As someone who works with data I can tell you that distributions can take on all kinds of unexpected shapes, especially when n=600. I think he's bluffing - the stats can't prove that anyone has cheated. That said, the deal he offered sounded pretty good when compared to the alternative.

paulgb 16y ago
My thoughts exactly. If I were a non-cheating student in that class, I would be very tempted to confess anyway, out of fear that I would be a victim of the prof's over-confidence in his statistical analysis. He mentioned being able to supply the dean with a list of people with 95% confidence that everyone who cheated was on the list, with no apparent concern for any false positives. The confession offer is pretty good in comparison.
- homonculus 16y ago
  "He mentioned being able to supply the dean with a list of people with 95% confidence that everyone who cheated was on the list, with no apparent concern for any false positives." Right after that, he said that he couldn't be sure everyone on the list had cheated. He is saying that he thinks every cheater is on the list, but not everyone on the list is a cheater.
  - paulgb 16y ago
    Right, that's not too impressive though, the class register would have everyone who cheated on it with 100% confidence.
sequoia 16y ago
I, as a non-statistician, agree that he was bluffing. If I were a student in that class with a high grade, cheating or no (because even the innocent may get accused and face the ostensibly severe consequences), I would be thinking "Hmm... Now how exactly does he plan on proving that I cheated?" Without a confession or third party who could reliably state that they know hypothetical-I was cheating, the possibility of actually proving misconduct on an individual level seems extremely remote. I would love to hear some statistics folks weigh in on this. Or: speculation ftw!
runningdogx 16y ago
That assumes that proof of anything is required. That's not usually how college disciplinary actions work. At its worst, universities will sometimes assume a student accused of wrongdoing is lying, and punish the student based solely on the word of the faculty/staff bringing the charge. This happens in lesser cases where the administration thinks it can get away with it, and when the student is frightened of harsher sanctions that might be inflicted if the student asserts his or her rights and demands a full hearing process. At its best (typically in more serious cases), the disciplinary process resembles a civil case (except instead of a jury, it's more of a tribunal) where the required proof is a preponderance of the evidence. It's no wonder 200 students confessed. If I was in that class and I'd never seen the test bank, I'd have confessed too. It's been my observation that the disciplinary process is better at railroading not-provably-guilty students than punishing provably-guilty students. I would not want to take my chances.

gojomo 16y ago

Perhaps this was the first semester that what had been known to a few people, or whispered about, became widely known. Perhaps this was the first time a digitized copy of the test bank got widely distributed -- maybe even because the publisher's standards for selling the test bank got loosened. At a smaller but growing scale, over several semesters, this tactic of using the test bank might not lead to any striking anomalies in the distribution... just a gradual rise in the average, and fattening of the above-the-median tail. For a while, that might convince the professor he's doing better! (Also, while we see Summer scores for comparison, he doesn't show the prior Spring or Fall. Often Summer students are a different pool, who in this case may not have been privy to the same campus folklore. Perhaps there was evidence of the same tactic earlier, or another professor with a different exam style taught previously.) Lots of speculation, I know, and I would need more information to assign levels of culpability overall. Were students specifically warned off using test bank questions? Did those who obtained the questions lie to the publisher to acquire them? How similar were the circulated test bank questions to other official preparation materials? Etc. It could also be interesting to see, on the makeup exam with presumably all-new but similarly-difficult questions, has the average mastery gone up? Perhaps memorizing the test bank questions does have some persistent beneficial effect for understanding the material.