Cluster Analysis: Difference between revisions

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Created page with "Category:R = Cluster Analysis = == Formatting the Data == <pre> > mydata <- na.omit(mydata) # listwise deletion of missing > mydata <- scale(mydata) # standardize variable..."
 
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== Kmeans Clustering ==
== Kmeans Clustering ==
<pre>
> fit <- kmeans(mydata, 5) # 5 cluster solution
# get cluster means
> aggregate(mydata,by=list(fit$cluster),FUN=mean)
# append cluster assignment
> mydata <- data.frame(mydata, fit$cluster)
</pre>


== Hierarcheal Clustering ==
== Hierarcheal Clustering ==

Revision as of 03:58, 15 February 2012


Cluster Analysis

Formatting the Data


> mydata <- na.omit(mydata) # listwise deletion of missing
> mydata <- scale(mydata) # standardize variables

#  (Opyional) Determine number of clusters
> wss <- (nrow(mydata)-1)*sum(apply(mydata,2,var)) for (i in 2:15)
> wss[i] <- sum(kmeans(mydata, centers=i)$withinss)
> plot(1:15, wss, type="b", xlab="Number of Clusters", ylab="Within groups sum of squares")


Kmeans Clustering

> fit <- kmeans(mydata, 5) # 5 cluster solution
# get cluster means 
> aggregate(mydata,by=list(fit$cluster),FUN=mean)
# append cluster assignment
> mydata <- data.frame(mydata, fit$cluster)

Hierarcheal Clustering