If you enter "#N/A" (without quotes) or the formula =NA(), then that
will be ignored in the chart display.

In article ,
"Iop.kcl" wrote:

We are entering data on questionnaires completed by parents and drawing
graphs from these. However, where data is missing X-cel gives a value of 0
which is scewing results. We are wanting to know what variable to use for
missing data.