SCRIPT FOR DATA SET 2 FOR CSC 120 ASSIGNMENT 2.

Read the function defintions.

> source("http://www.cs.utoronto.ca/~radford/csc120/a2funs.r")

Read the inputs and classes for the training cases.

> train_x <- read.table ("http://www.cs.utoronto.ca/~radford/csc120/a2trainx2",
+                         head=TRUE)
> train_y <- scan ("http://www.cs.utoronto.ca/~radford/csc120/a2trainy2",
+                  character())

Read the inputs for test cases.

> test_x <- read.table ("http://www.cs.utoronto.ca/~radford/csc120/a2testx2", 
+                        head=TRUE)

Classify the test cases with the original inputs, putting the guessed classes in 'cl'.

> cl <- classify (train_x, train_y, test_x)

Classify the test cases using rescaled inputs, putting the guessed classes in 'cl_rescaled'.

> rescale <- function (datax) 
+ {
+     datax$age <- datax$age / 10
+     datax$BP <- datax$BP / 100
+     datax$chol <- datax$chol / 100
+     datax$rate <- datax$rate / 100
+ 
+     datax
+ }
> 
> cl_rescaled <- classify (rescale(train_x), train_y, rescale(test_x))

Read the actual classes for the test cases.

> test_y <- scan ("http://www.cs.utoronto.ca/~radford/csc120/a2testy2",
+                  character())

Print the classification accuracy with the original inputs and the rescaled inputs.

> cat ("Classification accuracy with original inputs:", 
+       mean (cl == test_y), "\n")

Classification accuracy with original inputs: 0.625 

> cat ("Classification accuracy with rescaled inputs:", 
+       mean (cl_rescaled == test_y), "\n")

Classification accuracy with rescaled inputs: 0.7416667