<avg value="{sum(datum/@value)/count(datum/@value)}"/>

I think that Joerg meant to write
  <avg value="{sum(datum/@value) div count(datum/@value)}"/>
instead.

Cheers,
Stuart

-----Original Message-----
<xsl:template match="data">
<!-- selects the first datum/@value with not a following datum/@value

less than this one -->
   <min value="{datum[not(../datum/@value &lt; @value)]/@value}"/>
   <!-- selects the first datum/@value with not a following datum/@value

greater than this one -->
   <max value="{datum[not(../datum/@value > @value)]/@value}"/>
   <!-- like in mathematics: avg = sum / count -->
   <avg value="{sum(datum/@value)/count(datum/@value)}"/>
</xsl:template>

Regards,

Joerg