The sums-of-squares tag has no wiki summary.
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Are the sequential sum of squares appropriate when treatments must be applied in sequence?
I'm working with some modeled future stream flow data that was created in two steps. First, future precipitation predictions (at certain points in a watershed) were created by running historical ...
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2answers
55 views
Why is the k-means algorithm minimizing the within cluster variance?
I have read that the k-means algorithm tries to minimize the within cluster sum of squares (or variance). With some brainstorming, a question popped up. Why is it that k-means or any other clustering ...
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0answers
22 views
How to Partition An Interaction SS in ANOVA
I'm a new user of R and I'm trying to replicate Table 6.18 on page 262 in Statistical Procedures in Agricultural Research, By K. A. Gomez and A. A. Gomez. New York, Chichester, etc.: Wiley (1984). ...
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132 views
Type III sums of squares
I have a linear regression model with one categorical variable $A$ (male & female) and one continuous variable $B$.
I set up contrasts codes in R with ...
4
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1answer
173 views
R, Differences between lm and aov
What does explain the differences in p.values in the following aov and lm ?
Is the difference only due to different types of Sum of square calculations ?
...
3
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1answer
71 views
Assessing quality of clusters
I am running into problem of assessing the quality of clusters. In my case, I have plotted the data after determining data classes. For each class (1, 2, 3) there are two clouds that appear separately ...
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1answer
69 views
Monette & Fox's conditional hypotheses
G. Monette and J. Fox provide in these slides a framework for the Type II Analysis of Variance/Deviance tests in terms of conditional hypothesis. My questions are:
In this frequentist approach, the ...
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2answers
146 views
Which are the correct sum of squares for repeated measures ? (balanced example)
Below are three ways to fit a MANOVA model in R and to extract ANOVA tables from the fitted model. The design is balanced. All methods give different results.
The data are 5 groups of 4 individuals ...
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62 views
Type I ANOVA tests not depending on the order of the factors
I have a dataset with two factors A and B and the following design (contigency table showing the number of individuals for each ...
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0answers
106 views
Expectation of Sums of Squares
$\mu$=mean, $\sigma$=standard dev
show that if $H_0:\mu_1=...=\mu_k$ in the normal one way classification then
the Total Sum of Squares has expectation $E(T)=(N-1)\sigma^2$
the Within Groups Mean ...
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1answer
142 views
Comparison of k-means clustering output
I am trying to compare the outputs of k-means algorithm coded by me and the outputs of R's kmeans. Since the objective of the algorithm is to minimize the total ...
1
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1answer
147 views
Significance of the component in a multivariate linear model (“within-design”)
I'm trying to test the significance of the "component" effect in a multivariate regression model. I'm not sure what is the right way. Using R, I have tried a way with ...
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0answers
56 views
Different Mean Square partitions in an unbalanced bifactorial ANOVA (with random factor) between R and Statistica
I am trying to extract variance components for selection and chance in a bifactorial design with Generation as a fixed factor and Replicate as a random term, for early fecundity.
Since I am using ...
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0answers
97 views
Sum of Squares reduction test: Convergence criteria met, but not all parameters of the model estimated
Background: I am using weighted non-linear regression to model the growth of plant organs, with dummy variables for different species. I am using a sum of squares reduction test (SSRT) to compare the ...
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1answer
1k views
How to calculate sum of squared errors (SSE or SSR) with STATA12 software?
I have a techincal issue with stata: I need to calculate the SSE of a regression model, but the automatic output just gives me RMSE; I need SSE of this constrained model because I have to test if this ...
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1answer
262 views
Unique variance with regression analysis
I have some questions about unique variance and hope some of you can help.
For instance, let say I have 3 predictors and 1 dependent variable (DV).
I ran a regression analysis with a sequence of 3 ...
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0answers
15 views
How do I get the SSE for predictions using SAS? [duplicate]
Possible Duplicate:
How to get SSE for predictions using SAS?
I'm trying to get the sum of squared errors for my predictions in SAS, but I'm not sure I'm doing it correctly. I'm not sure ...
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1answer
205 views
How to get SSE for predictions using SAS?
I have a data set with some predictors, a number of training points, and some test points. I've come up with a model that I believe most accurately represents the training data (throwing out x1 and ...
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0answers
600 views
Effect Size/Mean Squared Error from Linear Mixed-Model in R
I'm trying to report an effect size for a Linear Mixed-Model we've fitted in R. Right now I'm looking at reporting partial eta squared or eta squared. However, to do so I need to calculate the Sums of ...
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182 views
Missing cells with Type III SS
I have a linear model of the form y ~ x + z + x:z.
I have unbalanced data and further have a few missing cells (data would be unbalanced even without those missing cells).
My understanding of the ...
2
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1answer
97 views
Proper order of variables in unbalanced ANOVA
If you have unequal sample sizes in cells, then the order in which you enter model terms changes your results for sequential or Type I SS. The first variable to enter the model is allocated its ...
3
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1answer
900 views
Distribution of sum of squares error for linear regression?
I know that distribution of sample variance
$$
\sum\frac{(X_i-\bar{X})^2}{\sigma^2}\sim \chi^2_{(n-1)}
$$
$$
\sum\frac{(X_i-\bar{X})^2}{n-1}\sim \frac{\sigma^2}{n-1}\chi^2_{(n-1)}
$$
It's from the ...
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1answer
606 views
Where is the shared variance between all IVs in a linear multiple regression equation?
In a linear multiple regression equation, if the beta weights reflect the contribution of each individual independent variable over and above the contribution of all the other IVs, where in the ...
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278 views
Sum of Chi-squared Variables
What is the distribution of the variable $Y$ which is given by
$$Y = \sum^N_{i=1} Z_i X_i $$
where :
$Z_1,\dotsc,Z_N$ are independent and identically distributed and the density function $f_Z(z)$ is ...
3
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1answer
417 views
Using and interpreting type I SOS in three-way ANOVA
My research question is from education: To test whether groups (university, department, gender) differ based on their scores in a test, and whether there are any interaction effects, I'll do 3-way ...
3
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1answer
555 views
Analysis of variance table for 2x2 cross-over trials
I am trying to reproduce the anova table for a 2x2 cross-over design. I used the data listed in tables 2.1 and 2.2 of the "Design and Analysis of cross-over trials" book, by Jones and Kenward. I am ...
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1answer
2k views
How to interpret type I (sequential) ANOVA and MANOVA?
My primary question is how to interpret the output (coefficients, F, P) when conducting a Type I (sequential) ANOVA? My specific research problem is a bit more complex, so I will break my example into ...
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2answers
685 views
GLM on unbalanced design
I have a dataset that comprises 200 males and 250 females and I am testing their responses on the relationship between X and Y.
X and Y are continuous and X1 (gender) is categorical.
I am using ...
-1
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2answers
128 views
Similar sum of squares in GLM
I have run the General Linear Model in SPSS to analyse the effect of several demographic variables (e.g. gender, age) on the relationship between X and Y.
So essentially, this is an analysis to see ...
2
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2answers
808 views
Collinearity between categorical variables
There's a lot about collinearity with respect to continuous predictors but not so much that I can find on categorical predictors. I have data of this type illustrated below.
The first factor is a ...
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2answers
2k views
How to specify specific contrasts for repeated measures ANOVA using car?
I am trying to run a repeated measures Anova in R followed by some specific
contrasts on that dataset. I think the correct approach would be to use
Anova() from the ...
2
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0answers
218 views
How to implement a weighted 3-way ANOVA in unbalanced design?
I have implemented a three-way anova with type III sum of squares in c++. Since some of my experiments (observations) are more important (more informative), I want to give them a higher weight in my ...
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1answer
560 views
The effect of the number of replicates in different cells on the results of ANOVA
I have written 3way-anova in c++. I have 3 factors, lets say a,b and c and my aim to check the strength of all possible interactions and main effects.The result of my code is the same as MATLAB when I ...
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4answers
1k views
Should I include an argument to request type-III sums of squares in ezANOVA?
I developed the ez package for R as a means to help folks transition from stats packages like SPSS to R. This is (hopefully) achieved by simplifying the specification of various flavours of ANOVA, and ...
11
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4answers
4k views
How does one do a Type-III SS ANOVA in R with contrast codes?
Please provide R code which allows one to conduct a between-subjects ANOVA with -3, -1, 1, 3 contrasts. I understand there is a debate regarding the appropriate Sum of Squares (SS) type for such an ...
