For the situation described in Problem 8.7, modify the data for X1, X2,. . . , X9 as follows.

 For the first 25 cases, add 10 to X1, X2, X3.

 For the next 25 cases, add 10 to X4, X5, X6.

 For the next 25 cases, add 10 to X7, X8.

 For the last 25 cases, add 10 to X9.

Now perform a cluster analysis to produce four clusters. Use two different programs with different options. Compare the derived clusters with the above groups.