The data above, reveal the fundamental limitation of functional testing: the twin possibilities of
gaps of untested functionality
redundant tests
For example:
The decision table technique for the NextDate program generated 22 test cases (fairly complete)
The worst case boundary analysis generated 125 cases. These are fairly redundant (check January 1 for five different years, only a few February cases but none on February 28, and February 29, and no major testing for leap years).
The strong equivalence class test cases generated 36 test cases 11 of which are impossible.
There are gaps and redundancy in functional test cases, and these are reduced by using more sophisticated techniques (i.e. Decision Tables).