Create a vector of ones which has the number of rows equal to the number of columns in the matrix data and 1 column
So if data is 100x10
data = randn(100,10);
then
y = ones(size(data,2),1);
creates a vector y that is 10x1.
If data is 100x1000
then
y = ones(size(data,2),1);
creates a vector of 1s that is 1000x1
