Sub getCounts()
    For i = 2 To 151672
        letter = Left(Cells(i, 1).Value, 1)
        asciiCode = Asc(letter)
        
        whatRow = asciiCode - 63
        
        Cells(whatRow, 14).Value = Cells(whatRow, 14).Value + Cells(i, 3).Value
    Next i
End Sub

Sub findClassSize()
    
    classSize = Cells(2, 7).Value
    
    For i = 1 To classSize
        r = Rnd
        
        For j = 2 To 27
            If r <= Cells(j, 1).Value Then
                Exit For
            End If
        Next j
        
        Cells(j, 3).Value = Cells(j, 3).Value + 1
    Next i
End Sub