If a "t" test is performed for the two treatments
with the largest difference (e.g., traditional vs. T + new
variety), a procedure that is not statistically orthodox,
the following would result:

 t = (xl x2 ) / Sx-x2

 = (6.15 4.1) / 0.4924
 = 4.1629

There are 2(r-l) = 2 degrees of freedom, where r = number
of replications or blocks. The calculated t values for 2
degrees of freedom are 2.920 for a 10% level of
significance and 4.303 for a 5% level. Hence, in this
case, the use of the new variety is not significant at the
5% level, but there is a strong indication that it does
make a difference in yield under these otherwise
traditional practices. Because the seed cost of maize is
a relatively small proportion of total production cost,
this may still be worth testing further.
 The step by step procedure for calculating the above
t value is as follows:


 S- = (2S-2/ r)1/2
 x -x x
 l-X2
 = [2(0.2425) / 2]1/2
 = 0.4924
and
 2 2 2
 S- = (S + S ) /
 x 1 2
 = (0.08 + 0.405) / 2
 = 0.2425
and
 S12 = EXl2 / (r-l)
 = 0.08 / 1
 = 0.08

 Exl2 = EXl2 [(EXl)2 / r]
 = [(4.3)2 + (3.9)2] [(8.2)2 / 2]
 =[18.49 + 15.21] (67.24) / 2]
 = 0.08