Perform principal component analysis on the accompanying data set.
a. Use the data with the covariance matrix to compute the seven principal components. How many principal components do you need to retain in order to account for 80% of the total variance? What are the weights for computing the first principal component scores?
b. Use the data with the correlation matrix to compute the seven principal components. How many principal components do you need to retain in order to account for 80% of the total variance? What are the weights for computing the first principal component scores?
c. Comment on the differences in the results of part a and b.