Challenging 'AVERAGE' Advance Task - need helps

Hiya everyone,

recently i have use MS Excel in my research, and have problem to get some advance averaging task done.

The row to solve:
0.4455
0.3812
0.3234
0.5012
0.3745
0.1102
0.3455
0.3129
0.3314
0.4112
0.3099
0.4472

The thing i would like to do is to create AVERAGE for the first 3 numbers (0.4455, 0.3812, and 0.3234), then next 3 (0.5012, 0.3745, and 0.1102), and so on and so forth.. After that put the average number in the SAME ROW as 0.3812 (2nd row), 0.3745 (5th row), and so on and so forth, but in the second column. The place to put each average solution are in the exact middle row of the 3-used-averaging values. However, I cannot do it manually as the data I am analysing is having 15000 values (above just a part of it). In another words, I must use an automatic function to do it.

Can anyone helps?

Many thanks.


Regards,
Jaan

To add on, there can be more than 1 function as long as it can automatically do the average and put it in the required position.