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Kynda
Level III

What is simplified definition of TypeI,II,III SS ANOVA?

My background is not mathematics and I do not really understand what this mathematical symbols means: Type I SS: SS(A) SS(B|A) SS (A*B|A, B) Type II SS: SS(A|B) SS(B|A) SS (A*B|A, B) Type III SS: SS (A|B, A*B) SS (B|A, A*B) SS (A*B|A, B)?

As I've understood; Type II is only when we don't have an interaction. But I've not convinced what the difference between TypeI and Type III?

What is the simplified definition of TypeI,II,III SS ANOVA?

1 ACCEPTED SOLUTION

Accepted Solutions

Re: What is simplified definition of TypeI,II,III SS ANOVA?

Type I sum of squares are also called sequential sum of squares because they are considered successively, so the order that you enter terms in the model (i.e., list of Effects in Fit Model launch dialog) is important. They are not the default test in JMP. They are obtained from the platform menu with the Sequential Tests command.

Type II sum of squares are not available in JMP.

Type III sum of squares is the default test in Fit Least Squares. They represent the additional sum of squares attributed to the given term. They are not dependent on the order of the terms.

As Jim advised, you can find more information by searching or in any applied regression textbook.

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3 REPLIES 3
txnelson
Super User

Re: What is simplified definition of TypeI,II,III SS ANOVA?

There is a plethora of sources on the description of Type I, II and III Sums of Squares.  Just go to your favorite search engine and type in:

     type i type ii type iii sum of squares

Jim
Kynda
Level III

Re: What is simplified definition of TypeI,II,III SS ANOVA?

"If you can't explain it simplyyou don't understand it well enough." - Albert Einstein 

As an idiot, I know how to surf & dive in these search engines. But I'm not that much smart enough to understand this. That's why I've asked the help from so-called mathematicians and statisticians. If you are not one of them, could you please do not give BS answers!!! Please.

Re: What is simplified definition of TypeI,II,III SS ANOVA?

Type I sum of squares are also called sequential sum of squares because they are considered successively, so the order that you enter terms in the model (i.e., list of Effects in Fit Model launch dialog) is important. They are not the default test in JMP. They are obtained from the platform menu with the Sequential Tests command.

Type II sum of squares are not available in JMP.

Type III sum of squares is the default test in Fit Least Squares. They represent the additional sum of squares attributed to the given term. They are not dependent on the order of the terms.

As Jim advised, you can find more information by searching or in any applied regression textbook.