Well, it's finally over! Here's a recap of my random thoughts on the final exam:

- In general, the final was harder than I expected. I'm pretty sure I did well, but it was definitely harder than the midterm and harder than I thought it would be.
- He hit us with 10 straight questions from Chapter 12 right out of the block! I expected to ease into it. The previous quarter's final was pretty linear - starting at chapter 7, then chapter 8, etc and not hitting chapter 12 until the last questions. I knew chapter 12 would be a big chunk of the exam, but I didn't expect him to lead off with it.
- I think we were all pretty stumped by that one question (was it 9 or 10?) that had us calculate the intercept, b
_{0}. I kept coming up with 100 for an answer, but it wasn't one of the choices. I saw Azzam go up and ask about something and figured it might be that. So I went up and asked also. I think we all breathed a sigh of relief when he made the change to the last two choices. BTW, I think he could have just changed Σ Y to be 100 and that would have made the intercept 40, which was one of the choices. - Probability of Type I errors? Sheesh! I didn't see that coming. The answer is that it's alpha, α.
- I was surprised at the "regular" question that had us work out the regression from the raw data. I'm almost positive I made some arithmetic mistakes in calculating the Σ(X
_{i}-Xbar)(Y_{i}-Ybar) or Σ(X_{i}-Xbar)^{2}or one of the other calculations. - My answer for the "west nile" question was that we do not reject the null hypothesis, H
_{0}that the average # of cases is different than 3. - On the last question, part A, you had to assume (or somehow know through ESP or divine vision) that the level of confidence to use is 95%. You can calculate the t-score easily enough (I think I got something like 2.414), but draw any conclusions, you need to calculate the critical value for t
_{α/2, n-1}which requires the level of confidence. - I knew there would be a Durbin-Watson question on the exam! My answer for that one was that there was not evidence of autocorrelation since the DW stat was greater than d
_{U}and less than 2+d_{L}. I'm not sure I was using the right d_{U}because I wasn't sure if I should use α or α/2 on the DW table. I used α (which I think was 0.05). - As predicted, there were a few questions with Minitab output. No big surprises there.
- In at least 2 of the questions (one multiple choice and one "regular"), he gave us the variance rather than the standard deviation. Tricky! I almost fell for that one.
- One question asked us to determine sample size, given a confidence level, margin of error and standard deviation (or maybe variance). Using the formula, you calculate n=74.3 (something like that - not a round number). You had to know to round up, not truncate the decimal.
- Higher confidence levels need wider intervals. You had to figure he would ask about that.
- If p is low, H
_{0}must go! You could use that to answer one of the multiple choice question on p-value approach in hypothesis testing.

## 2 comments:

now the only question is... when is he going to get the grades back! :)

Great get-together after the test by the way, had a lot of fun.

I've enjoyed your blog very much. Was following it throughout the quarter. Good luck with other classes as well...

Cemil

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