
(data "French"
:about "These data are from a study in which teachers took a test for understanding French both before and after taking a summer course in French. Data for Univariate Analysis. They may be analyzed as paired samples by choosing both of the PreTest and PostTest variables, or as a single sample by choosing the Difference variable. Data are from Moore, D.S. and McCabe, G.P. Introduction to the Practice of Statistics 2nd Ed., p. 508. "
:title "Understanding French"
:variables '("PreTest" "PostTest" "Difference")
:data 
(let* ((pre-test 
        (list 32 31 29 10 30 33 22 25 32 20 30 20 24 24 31 30 15 32 23 23))
       (post-test 
        (list 34 31 35 16 33 36 24 28 26 26 36 26 27 24 32 31 15 34 26 26))
       (difference (- post-test pre-test)))
  (combine 
   (transpose (matrix '(3 20) (combine pre-test post-test difference))))))