Letters = Numbers

[oberon.black]

I want to use 'ms'=4 , 's'=5, 'p'=2, 'j'=10
so that when I type these letters into a cell I can then run an average based on the letters that will come back with a numeric figure.

How do I do this?

[swatsp0p]

You could use a helper column to set a value based on the contents of the cells, e.g.:

=CHOOSE(MATCH(A1,$F$1:$F$4),4,5,2,10) copied down in col B with your list of criteria in F1:F4 (ms,s,p,j) would read the cells in Col A and return the listed values or #N/A if not matched.

Then =AVERAGE(Bn:Bnnn) gives you the average of this range

Does this work for you?