Nick
I do a race report card featuring various averages and variances e.g. Forecast average TWS versus actual average TWS.
There are various ways to calculate the actual values, but the easiest is to highlight the whole race (Start-Finish) in Stripchart and read off the stripchart.  However, in my absence with a bad back the boys had a 3 hour instrument outage in a 23 hour race.  Would the blank values for that period have any impact on the calculation of basic stats?