OneWay ANOVA in Inference App

12192016, 10:10 PM
Post: #1




OneWay ANOVA in Inference App
I am going through the User Guide to test the latest release and for my own review. I entered some data for four groups like this into the Inference app:
MAKELIST(RANDNORM(50,3),X,1,10) STO> I1 (through I3) and MAKELIST(RANDNORM(53,3),X,1,10) STO> I4 So I have generated random samples of size 10 from four populations, where the last of them is different by a mean of 3. Then I tested the null hypothesis with the oneway ANOVA. I confirmed this result in the Num view: F: 3.207 (correct) P: 0.03446 (correct) But I was surprised to see this result in the Plot view: ChiSquare: 10.8849 (?) P: 0.03446 (correct) My questions are: Why is Chi square in the plot view? Where does the Chi square statistic come form? Is the graph in the Plot view for a Chi square distribution or the F distribution? Thanks! 

12202016, 12:49 AM
Post: #2




RE: OneWay ANOVA in Inference App
I'm guessing it might be plotting when it shouldn't there. I'll take a look at it. I don't think there is a plot view currently for Anova. Thanks!
TW Although I work for HP, the views and opinions I post here are my own. 

12212016, 01:55 PM
Post: #3




RE: OneWay ANOVA in Inference App
Well, a plot view with the F PDF and the sample statistic, as done for t tests, might be great for interpretation and instruction of ANOVA.


12212016, 02:40 PM
(This post was last modified: 12212016 02:41 PM by Tim Wessman.)
Post: #4




RE: OneWay ANOVA in Inference App
I remember implementing this, so it was strange it wasn't displaying right.
I looked into the source today. Looks like the root culprit was a missing "break" in a switch statement which causes the *label* to display incorrectly as chi2. The graph itself is correct, but the wrong text for the front half/value are being shown. Testers missed this one (and I screwed it up of course ). Thanks! It should read DF:<num> F:<val> P:<val>. TW Although I work for HP, the views and opinions I post here are my own. 

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