Hi,

When I plot a calibration graph (concentration vs response) and add a trend
line, Excel will show the gradient and intercept of the line. I normally
capture these in a couple of cells, either using the SLOPE and INTERCEPT
functions, or using LINEST.

Sometimes, however, there is a data point missing, and although the chart
will continue to give the gradient and intercept, the functions give either
#N/A or #VALUE errors.

I've tried getting the missing data points to return #N/A or "", but can't
seem to get it to work.

Any ideas, please?

Thanks

Dave

url:http://www.ureader.com/gp/1042-1.aspx