This is a portion of R.A. Fisher's Iris Flower Data set, for classifying iris 
species based on plant measurements.  The first four X columns are petal 
length, petal width, sepal length, and sepal width, and the last column is the 
species Y (0=seotsa, 1=virginica).

To load into Matlab for logistic regression, do the following:
iris=csvread('iris.data');
X=iris(:,1:4);
Y=iris(:,5)