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Course Documents

Chapter 1 - Intro

Chapter 2 - Methods for Describing Sets of Data

Chapter 3 - Probability

Chapter 4 - Discrete Random Variables

Chapter 5 - Normal Random Variables

Chapter 6 - Sampling Distributions

Chapter 7 - Confidence Intervals

Chapter 8 - Tests of Hypothesis: One Sample

Chapter 9 - Confidence Intervals and Hypothesis Tests: Two Samples

Sample Exam I: Chapters 1 & 2

Sample Exam II: Chapters 3 & 4

Sample Exam III: Chapters 5 & 6

Sample Exam IV: Chapters 7 & 8

Hi Professor Im struggling with a questions that seems pretty simple!

Ch. 10 #3 in the homework. Im doing everything right except for the SST, I'm adding 1368squared/4 + 1279squared/4 + 1471squared/4 + 1454squared/4 = 1946305.5

Then i go on to do the SSE and I subtract 31121.333-1946305 and get -1915183.667

I don't know what I'm doing wrong

Posted to **STATS 2** on Monday, November 10, 2014 Replies: 6

11/10/2014

10:06 PM EST

Hi Sandra,

You haven't subtracted your correction factor from the 1,946,305.5. Don't forget the correction factor** **is **(Σy)²** **/N. **

Hope that helps,

Professor McGuckian

11/11/2014

9:59 PM EST

Thank you!!!!

I have another quick question, for number 12 in chapter 11 homework, why is it that you subtracted the times 150-146 to find the prediction error?

I have another quick question, for number 12 in chapter 11 homework, why is it that you subtracted the times 150-146 to find the prediction error?

11/11/2014

10:47 PM EST

The prediction error is y - * ^{^}y . *The variable y represents the actual y value from the original data that corresponds to the x value they are using. The

11/12/2014

10:20 AM EST

Thank you again!

Hopefully this will be my last question!

for number 62 b in the chapter 11 mixed review

62. b What is the largest deviation you might expect between any one of the 6 points and the least

squares line (find a deviation that 95% of the observed values will fall within from our line)?

you posted the answer to be 2S which stands for 2 standard deviations? Sorry if it seems obvious but just want to make sure!

Hopefully this will be my last question!

for number 62 b in the chapter 11 mixed review

62. b What is the largest deviation you might expect between any one of the 6 points and the least

squares line (find a deviation that 95% of the observed values will fall within from our line)?

you posted the answer to be 2S which stands for 2 standard deviations? Sorry if it seems obvious but just want to make sure!

11/12/2014

10:45 AM EST

Just in case, can you show me how you got the answer for 62b. I keep getting the wrong one.

11/12/2014

11:08 AM EST

Hi Sandra,

If you understood part a, then part b is easy. Part a gives us the variance, s², so we just take the square root of the answer in part a and then multiply by two. The reason we multiply by two is that we assume the error terms have a normal distribution with a mean of zero. The empirical rule from STATS I tells us that approximately 2 standard deviations capture 95% of the data under a bell curve.

Professor McGuckian