Suvayu Ali dijo [Tue, Apr 09, 2013 at 02:25:19AM +0200]:

> On Mon, Apr 08, 2013 at 06:57:53PM -0500, Gunnar Wolf wrote:
> > #+CAPTION: Attendances for April
> > |---------+-------------------+---+---+---+---+----+-------|
> > | Account | Name              | 1 | 3 | 5 | 8 | 10 | Total |
> > |---------+-------------------+---+---+---+---+----+-------|
> > |    1234 | Cárdenas, Lázaro  | X |   | X | X |    |     3 |
> > |    5678 | Madero, Francisco | X | X | X | X |    |     4 |
> > |    1544 | Villa, Pancho     |   |   |   |   |    |     1 |
> > |    0113 | Zapata, Emiliano  |   | X | X |   |    |     2 |
> > |---------+-------------------+---+---+---+---+----+-------|
> > | Day avg | 2.25              | 2 | 2 | 3 | 2 |  1 |  2.50 |
> > |---------+-------------------+---+---+---+---+----+-------|
> > #+tblfm: @2$8..@5$8='(length '($3..$7))::@6$2=vmean($3..$7);%.2f::@6$3..@6$7='(length '(@2..@5))::@6$8=vmean(@2..@5);%.2f
>
> Probably not what you were looking for, why complicate things by using
> Xs instead of just a numeral like 1?  If you use 1, then you can use a
> column formula; maybe something like $>=sum($3..$-1).

I had though about it, and it's currently a last resort for me. I want
to publish the lists in the course's webpage, and while a '1' would do
for me, I'd rather present to the students something they are more
likely to understand as natural.