# Section A01

This quiz focused on exponential smoothing. Make sure that you know about moving averages and autocorrelation too.

### #1

You needed to find the biggest decline in the time series. You should never have to guess in stats, and I'm worried that some of you just looked at ...

# Section A01

## #2

Remember that for the modified best conservative model, we still care about the significance of all the predictors other than the ones that must be included.

## #3

Quite a few people are still giving point estimates (just $$\hat{y}$$) when the ...

## #1

The test statistic for $$H_0: \beta_1 = \beta_2 = 0$$ is the $$F$$ statistic. It's what we'll use for when we're testing multiple parameters at once.

Several people had $$\beta_1 = 0$$ or $$\beta_2 = 0$$. This is wrong; it should be and not or. This is actually an important ...

4. ## Quiz 6 Review

Part b asked for a CI for the slope $$\beta_1$$. For this one you use the formula $$\hat{\beta_1} \pm t^{\ast}_{n-p-1} SE(\hat{\beta_1})$$. $$n$$ is the sample size and $$p$$ is the number of predictors (1 in this case).

You get the $$\hat{\beta_1}$$ and $$SE(\hat{\beta_1})$$ ...

## Problem 1

Make sure to read the questions carefully, in particular the underlined or bold parts. For this question we wanted the statistical concept that explains why interpreting a prediction for a car with 0 City MPG is mislaeding. I agree with many of you that a negative Highway MPG ...

6. ## Quiz 4 Review

Some people were circling the samples. ANOVA is all about comparing how spread out the means are relative to how spread out the samples are. If two means are far away (relative to how spread out the samples are) the means will be in separate clusters.

The number of clusters ...

7. ## Quiz 3 Review

Take a look a ICON for the solutions on this one. There's a brief explanation of each answer. It's harder to give feedback on this one since it's multiple choice, so email me if you have any questions.

Remember that this week's homework was over $$\chi^2$$ ...

8. ## Quiz 2 Review

Much better this week! Keep it up. If you see (half) anywhere on your quiz that means that you missed an earlier question, which caused you to miss the later question. So you did everything correct on the later question, but you didn't get the right answer because of ...

9. ## Quiz 1 Review

• General remarks

• read the questions carefully, especially the bold and underlined parts.
• The full solutions are on ICON.
• Section A01

• Section B42

## Section A01

### #1

• Don't mix up the sample statistic with the sample. The sample is a group of some objects (bars, people, etc.). The statistic is some ...