Question

I am new to Business Objects and more specifically Desktop Intelligence. We are trying to use it as a reporting tool for our scientific data but running into issues when performing calculations to “create” objects and then trying to perform statistical or aggregate functions on them. For example I run a query that pulls the columns subject name, result day, parameter, and result value. In a table it would look like this:

SUBJECT    DAY    PARAM      RV
10001      0      Length     5.32
10001      0      Width      4.68
10002      0      Length     3.98
10002      0      Width      1.64
10001      7      Length     8.89
10001      7      Width      7.30
10002      7      Length     4.17
10002      7      Width      2.19

We then use the equation for Volume: L*W^2*0.52 in the report defined as measure variable. Using a cross tab with days across the top and subjects down the side I display Length Width and Tumor Volume like such:

                     0                           7
SUBJECT     L        W        V         L        W        V
10001       5.32     4.68     60.59     8.89     7.30     246.35
10002       3.98     1.64     5.57      4.17     2.19     10.40
COUNT                           #                           #
MEAN                            #                           #

Within the footers I’d like to display aggregates such as count, standard deviation, percent change from day zero but they are all screwed up. It’s not that it’s also doubling the n by two either to account for the fact that Length and Width make up Volume. I have no clue and am at a loss. Any advice suggestions or guidance would be welcomed.

Thanks in advance,
Jeff

Answer 1

I assume that your cross tab looks like the following in Slice and Dice:

            ¦ <DAY> (Break)
            ¦ <PARAM>
  --------------------
  <SUBJECT> ¦ <RV>

So your table should look something like:

        0                          7        
        Length   Width   Volume    Length    Width    Volume
10001    5.32    4.68    60.59     8.89      7.30     246.35
10002    3.98    1.64    5.57      4.17      2.19     10.40

With <DAY>‘s break footer having the volume variable.
For your volume calculation I’ve used the formula: =(<RV> Where (<PARAM>="Length"))*(Power(<RV> Where (<PARAM>="Width") , 2))*0.52

Right click on the cross tab edge and select Format Crosstab... Then check the Show Footer check box in the Down Edge Display section of the General tab. Add extra rows in the footer if you need them.

Then manually add the formulas for count =Count(<VOLUME>) and mean =Average(<VOLUME>)

For me the final table now looks like this (With values rounded to 2dp):

        0                          7        
        Length   Width   Volume    Length    Width    Volume
10001    5.32    4.68    60.59     8.89      7.30     246.35
10002    3.98    1.64    5.57      4.17      2.19     10.40
Count                    2.00                         2.00
Mean                     33.08                        128.37

The trick is making sure the calculations happen in the right context (that is, with respect to the header variables in the different sections of the table). You can add and remove variables and context with the functions In, ForAll and ForEach. Although I haven’t needed to use them for this table.