My friend is enrolled in an introduction to statistics class at a community college, and she just sent me this question from her quiz:

(Click image for bigger version)

Her answer of "false" has been graded as incorrect. I assured her that the probability was 0.15 and therefore "false" was correct, so she e-mailed the professor.

The professor replied that "true" was indeed correct "because of the multiplication rule, 8/20 times 3/20." Despite her objections, he is leaving the answer as incorrect.

This is why you don't ever want to go to community college.

I wish we could actually set up the described bag and gamble on it if he really thinks the probability is 0.06 instead of 0.15.

Quote:sodawaterWell, this is infuriating.

My friend is enrolled in an introduction to statistics class at a community college, and she just sent me this question from her quiz:

(Click for bigger version)

Her answer of "false" has been graded as incorrect. I assured her that the probability was 0.15 and therefore "false" was correct, so she e-mailed the professor.

The professor replied that "true" was indeed correct "because of the multiplication rule, 8/20 times 3/20." Despite her objections, he is leaving the answer as incorrect.

This is why you don't ever want to go to community college.

I wish we could actually set up the described bag and gamble on it if he really thinks the probability is 0.06 instead of 0.15.

And I thought my college had issues with teaching. That's really frustrating, hopefully your friend has many opportunities to make points back, because with a professor like that it seems necessary!

Quote:tringlomaneMost of my college classes never gave questions like this too. Problems with extraneous information. Only one of my professors would sparingly, and he was one of my better teachers. It's a good idea to do it from time to time, imo.

Lol yeah it's only a good idea though if the professor himself is able to successfully answer the question.

On a regular six sided die, there are 3 odd numbered sides. On one of those odd numbered sides, there is also a sticker. Only that odd numbered side has a sticker. What is the probability of rolling the die and having it land with a sticker on the top face?

It should be intuitive, even to this instructor, that the probability is 1/6 and not 3/36. Hopefully, the instructor will be able to draw the correlation between the questions.

I agree that there is the potential for that non-rocket-scientist of a professor to get it wrong, but I suspect not.Quote:CrystalMathAsk the instructor this:

On a regular six sided die, there are 3 odd numbered sides. On one of those odd numbered sides, there is also a sticker. Only that odd numbered side has a sticker. What is the probability of rolling the die and having it land with a sticker on the top face?

It should be intuitive, even to this instructor, that the probability is 1/6 and not 3/36. Hopefully, the instructor will be able to draw the correlation between the questions.

I would instead add a second die and say that there are no stickers on that second die. When both dice are rolled, what's the odds of the sticker being face up?

Quote:CrystalMathAsk the instructor this:

On a regular six sided die, there are 3 odd numbered sides. On one of those odd numbered sides, there is also a sticker. Only that odd numbered side has a sticker. What is the probability of rolling the die and having it land with a sticker on the top face?

It should be intuitive, even to this instructor, that the probability is 1/6 and not 3/36. Hopefully, the instructor will be able to draw the correlation between the questions.

Meh. Don't try to confuse this kind of professor with logic. That a person could get to a Masters Degree and miss something so simple is just amazing.

I would give a pass if it was a case of, "crap, I worded that wrong." Looking at the prof's logic and I cannot even tell what they are trying to figure out.