The following code has some bug. As I've written it bellow, when calculating d using whatever variation of Rad (RadM, RadR, RadH...) the result is the same, although the values are different.

In[281]:= sp[val1_, val2_] := Sqrt[((2*Variance[val2]) + (2*Variance[val1]))/6]

In[282]:= d[val1_, val2_] := (Mean[val2] - Mean[val1])/sp[val1, val2]

In[283]:= sp[RadM, RadH]

Out[283]= 0.621

In[286]:= d[RadM, RadH]

Out[286]= 4.97[{7.3, 6.8, 8.2}, {10, 9.4, 11}]

The output value (check the above 2 lines) is 4.97 with the values used to derived that result written in brackets. If I chance from RadH to RadR for example, the second set of values (10, 9.4, 11) changes. But the final result, 4.97, never does.

The same in picture mod, if the code is not clear.