Data Mining Class Project

1. Clustering and Association Rules
Case 4
NOVEMBER 24, 2014
GROUP 7
Sushmita Dey
Nikolaos Minas
AllanKuo
Prof Shaonan Tian

2. Clustering
• Clustering is a popular
method.
• It groups a set of points
together in a . Objects different
from each other are grouped in
. The distance is used
as matric to separate objects to
.

3. Clustering
• Objects within same cluster are closer
to each other compared to objects in
different cluster.
• We used from the iris data
set to apply

4. K-Means Clustering
• We use k-means() function from the
“fpc” package.
• We started with number of cluster
equal to and the result was
of pure cluster,
of slightly less pure
cluster and the mixture of
and

5. K-Means Clustering
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6. Hierarchical Clustering with
hclust()
• We used hclust() function from the
“fpc” package
• We used War’s variance
method to create clusters
• We started with and
went upto

7. Hierarchical Clustering
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Figure 5: Centroid Plot with 3
Clusters
Figure 5: Centroid Plot with 4
Clusters

8. Association Rules
• Association rule is a popular
unsupervised
• Association rule is used in
in the retails stores to
find which items are
.

9. Association Rules
• Association rules are mostly suited to
find between items in
large set of transactional data
• A typical rule may be represented as:
• {peanut butter, jelly}-> { }
• If peanut butter and jelly are
purchased then

10. Apriori Algorithm
• Apriori Algorithm is used to learn
in a large
transactional dataset.
• Apriori algorithm employs a simple a
priori belief as a heuristic that all
of a set
must also be .
• We used the arules package from R to
analyze the Groceries dataset.

11. Groceries Data Sets

12. Data Exploration
• We install and load the package using the
commandsinstall.packages(“arules”
)and library(arules).
• We use R functions to explore the grocery
dataset.
• We use dim() function to find the
dimensions of the Groceries dataset
• We use inspect() function from
”arules” package to find the 1st 10
transactions in the data sets.

13. Data Exploration
• We use output from the summary()
function on the dataset to find most
frequently purchased item(
), items per average
transaction( ) and items in the
largest transaction # of items(32)
• We use the itemFrequencyPlot()
• Function to create plot from the dataset for visual
exploration
• We plotted item frequency plot for all the items
and items with support

14. Items frequency plot(All items)

15. Items frequency plot(Items with
10% support)

16. Associations Rules
•We use Apriori algorithm from the
arules package to generate set of
association rules.
•We generated rules using
support = and confidence =
by trying out different values
of support and confidence.

17. Associations Rules
• We use summary() function on rule set
to find the rule length distribution,
with rules containing one item.
• We found that generated rule sets
have quality metric of lift as
• We use inspect() and
sort()function to generate
sorted by .