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ASK THE PROFESSOR FORUM 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

# Ask the Professor Forum

Professor, for number 7 in hw 10.1: after trying to get the SST I keep getting a negative value and i am not sure why?

Posted to STATS 2 on Thursday, March 20, 2014   Replies: 1 Professor Mcguckian
03/20/2014
4:22 PM EST

Hi Natalie,

First you would need to calculate the totals for each of the three columns: 40°, 80°, and 120°.  The sums for each of these columns of data are: 228.4, 168.5, and 81.9 respectively. Then we need to know the correction factor.

CF = (the sum of all of the observations)²/n = 478.8²/18 = 12,736.08

Then SST is given by: (sum for 40°)²/n1 + (sum for 80°)²/n2+ (sum for 120°)²/n3 - CF = 228.4²/6 + 168.5²/6 + 81.9²/6 - 12,736.08 = 1808.3233333.

Hopefully, that helps you find your error.

Professor McGuckian