My first exam (Statistics 224) starts in 21 minutes, and I’m posting to the SDMB. Of course, it’s by far the easiest of the four finals I have this semester.
I’m not usually this random… heck, I rarely post in MPSIMS… but I thought I’d just like to share that. Besides, it’s snowing!
It’s quite cold in Madison, and snowing kind of heavily. I walked outside and a frantic flurry of large, fluffy flakes surrounded me as I started up the hill to the Psychology building. The university’s ground crews hadn’t started snow removal yet, so an inch or two of the white stuff crunched under my feet… actually, more like the “kafuzz, kazuzz, kazuff” of corduroy. The Test
After a nice ten minute walk in the 5 degree air, I reached the lecture hall (with seven minutes to spare), sat down, and pulled out my ever-so-carefully prepared notesheet. Seven minutes hence, the exams were handed out. The first two problems were incredibly easy, nothing more than re-writes of problems from the midterms. Those took no mroe than five minutes each. The third problem, concerning inferences using proportions, wasn’t very difficult either; once I realized I needed a chi-square distribution for a problem concerning three proportions (10 point in itself), it almost solved itself.
The fourth and final problem was what kept me from leaving after 40 minutes. It was just a least-squares linear regression problem, and most of it was not a challenge. However, just one little 5-point question was holding me up- I just couldn’t remember what a sample correlation coefficient was! I hadn’t written it in my notes, nor had I computed it on any assignments… I ended up playing with my calculator, dividing out different proportions and running the linear regression function until I found something reasonable. I wrote it down along with the steps I used to ‘calculate’ it, and turned in my exam. Total time elapsed: 63 minutes. The Aftermath
I left the lecture hall, and cracked open my text to the definition of ‘sample correlation coefficient’, and lo and behold, my answer, in the symbolic form I has written on my exam, was there! Not only had I calculated it correctly, but I had also accidentally derived the formula used to find it! Somehow, that made me feel really, really, good.