Re: [O] How to do a sum of products in a table?

[Rasmus]

Hi Alan,

> I'm grading an exam, and I'm trying to use org instead of Numbers to
> tabulate the results. For each student, I'll input how well he answered
> to the question, and his grade will be (sum of mark * coefficient),
> where each question has a different coefficient (in Numbers I was using
> the SUMPRODUCT function).
>
> Is there a way to do this in org mode?

Sure, but please provide an example.  E.g. is each student a column?
Or is the dotproduct of two vectors where mark is just one

Here's a prtty simple example

|   | nr. | score     | score |
|---+-----+-----------+-------|
| # |   1 | [1, 2, 3] |   4.2 |
| # |   2 | [3, 4, 5] |   7.8 |
#+TBLFM: $4=$3*[.3, .6, .9]

It would probably be nicer to have the weighting matrix externally
defined.  Perhaps you can use #+CONSTANTS or the remote function.  If
you prefer you can also let each

A more advance example is given in the manual:

  http://orgmode.org/org.html#Advanced-features

     |---+---------+--------+--------+--------+-------+------|
     |   | Student | Prob 1 | Prob 2 | Prob 3 | Total | Note |
     |---+---------+--------+--------+--------+-------+------|
     | ! |         |     P1 |     P2 |     P3 |   Tot |      |
     | # | Maximum |     10 |     15 |     25 |    50 | 10.0 |
     | ^ |         |     m1 |     m2 |     m3 |    mt |      |
     |---+---------+--------+--------+--------+-------+------|
     | # | Peter   |     10 |      8 |     23 |    41 |  8.2 |
     | # | Sam     |      2 |      4 |      3 |     9 |  1.8 |
     |---+---------+--------+--------+--------+-------+------|
     |   | Average |        |        |        |  25.0 |      |
     | ^ |         |        |        |        |    at |      |
     | $ | max=50  |        |        |        |       |      |
     |---+---------+--------+--------+--------+-------+------|
     #+TBLFM: 
$6=vsum($P1..$P3)::$7=10*$Tot/$max;%.1f::$at=vmean(@address@hidden);%.1f

Refer to

  http://orgmode.org/org.html#The-spreadsheet

–Rasmus

-- 
Hooray!