You can either create a column containing the differences and analyze it with a 1-sample t-test or Minitab now has a paired-sample t-test in its menu options.

We also discuss the two non-paramteric alternatives, the simple sign test and the more powerful signed rank test.

The following data were originally from Kacprzak and Chvojka (1976). I found them in Rice's: Mathematical Statistics and Data Analysis.

Fish SelectiveReduction Permanganate 1 .32 .39 2 .40 .47 3 .11 .11 4 .47 .43 5 .32 .42 6 .35 .30 7 .32 .43 8 .63 .98 9 .5 .86 10 .60 .79 11 .38 .33 12 .46 .45 13 .20 .22 14 .31 .30 15 .62 .60 16 .52 .53 17 .77 .85 18 .23 .21 19 .30 .33 20 .70 .57 21 .41 .43 22 .53 .49 23 .19 .20 24 .31 .35 25 .48 .40