Portfolio 2

Exercise 1: Tanimoto Score

Here is my Tanimoto score function:

# Returns the Tanimoto score for person1 and person2

def tanimoto_score(prefs,person1,person2):

  # Get the list of shared_items

  si={}

  for item in prefs[person1]: 

    if item in prefs[person2]: si[item]=1

  # if they have no ratings in common, return 0

  if len(si)==0: return 0

  # Add up the squares of all the differences

  tanimoto =sum([prefs[person1][item]*prefs[person2][item] / (pow(prefs[person1][item],2)+pow(prefs[person2][item],2)-prefs[person1][item]*prefs[person2][item]) for item in prefs[person1] if item in prefs[person2]])

  return 1/(1+tanimoto)

When I ran the function I got:

>>> recommendations.tanimoto_score(recommendations.critics,'Lisa Rose', 'Gene Seymour')

0.15581371067992209

To calculate the Tanimoto Score I used:

From: http://en.wikipedia.org/wiki/Jaccard_index#Tanimoto_coefficient_.28extended_Jaccard_coefficient.29

The Tanimoto Score is often used to find similarity between two documents.

Part 1: Weka

I found the Weka tool to be very easy to use. The program gives us a quick and easy way of analyzing the raw data from an ARFF file. I received the same answers as we were given.

Part 2: Cleveland Heart Disease Dataset

I downloaded the dataset in the ARFF file format, which made this part very quick to do. When I classified the the data I found,

Correctly Classified Instances: 77.558%

Incorrectly Classified Instances: 22.4422%

Total Instances: 303

I believe the J48 classifier is a fairly accurate method of analyzing data, however, I believe running several types of classifiers would help us predict more accurate information. When I ran the Random Forest classifier I found,

Correctly Classified Instances: 81.5182%

Incorrectly Classified Instances: 18.4818%

Total Instances: 303

The Random Forest classifier yielded more accurate information. When I ran the Decision Stump I yielded less accurate information than the J48 classifier.

Correctly Classified Instances: 71.6172%

Incorrectly Classified Instances: 28.3828%

Total Instances: 303

After the comparisons, I came to the conclusion that multiple classifiers should be ran when analyzingdatasets in order to give the best results possible.

I found that the majority of the people in the dataset were male (Total: 207) while women were the minority (Total: 96). The amount of people with fbs was 258 versus while 48 did not. The median age was 55.366 and thal was the first set of data on the tree.