Page 13 - Statistics II for Dummies

Table of Contents
Doing the F-Test ...........................................................................................162 xi
Running ANOVA in Minitab ..............................................................163
Breaking down the variance into sums of squares........................164
Locating those mean sums of squares ............................................165
Figuring the F-statistic .......................................................................166
Making conclusions from ANOVA ....................................................168
What’s next? .......................................................................................169
Checking the Fit of the ANOVA Model ......................................................170
Chapter 10: Sorting Out the Means with Multiple Comparisons. . . .173

Following Up after ANOVA .........................................................................174
Comparing cellphone minutes: An example ...................................174
Setting the stage for multiple comparison procedures ................176
Pinpointing Differing Means with Fisher and Tukey ...............................177
Fishing for differences with Fisher’s LSD ........................................178
Using Fisher’s new and improved LSD ............................................179
Separating the turkeys with Tukey’s test .......................................182
Examining the Output to Determine the Analysis ...................................183
So Many Other Procedures, So Little Time! .............................................184
Controlling for baloney with the Bonferroni adjustment .............185
Comparing combinations by using Scheffe’s method ...................186
Finding out whodunit with Dunnett’s test ......................................186
Staying cool with Student Newman-Keuls ......................................187
Duncan’s multiple range test ............................................................187
Going nonparametric with the Kruskal-Wallis test ........................188
Chapter 11: Finding Your Way through Two-Way ANOVA . . . . . . . . .191
Setting Up the Two-Way ANOVA Model ...................................................192
Determining the treatments .............................................................192
Stepping through the sums of squares ...........................................193
Understanding Interaction Effects .............................................................194
What is interaction, anyway? ...........................................................195
Interacting with interaction plots ....................................................195
Testing the Terms in Two-Way ANOVA ....................................................198
Running the Two-Way ANOVA Table ........................................................199
Interpreting the results: Numbers and graphs ..............................200
Are Whites Whiter in Hot Water? Two-Way ANOVA Investigates .........202
Chapter 12: Regression and ANOVA: Surprise Relatives! . . . . . . . . .207
Seeing Regression through the Eyes of Variation ...................................208
Spotting variability and finding an “x-planation” ...........................208

Getting results with regression ........................................................209

Assessing the fit of the regression model .......................................211
Regression and ANOVA: A Meeting of the Models ..................................212
Comparing sums of squares .............................................................212
Dividing up the degrees of freedom ................................................214
Bringing regression to the ANOVA table ........................................215
Relating the F- and t-statistics: The fi nal frontier ..........................216

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