I'm comfortable with most functions in Excel now and I've decided to complicate things by adding a chart to a project I'm working on. I've figured out how to get the data I want plotted on a simple line chart, but I'm hitting a snag. I've used the following formula to calculate the number I'm trying to graph...

=IF(COUNTA(B5)>0,((B5*C5)+(B5*D5)+(E5*F5))/B5,"")

The sheet is a review of the time it takes employees to complete their tasks over the course of a month, with stats for each day. If they didn't work on a certain day, there is no data at all. The formula just checks if there are values before calculating to prevent #!DIV0 errors from appearing and leaves the cell blank if there is not data present. When I try to graph though, these blank cells are causing the graph to drop off dramatically (it looks like the blank cells are being calculated as having a 0 value on the graph).

I've tried the options for ignoring blank cells, but I think that the "" may be causing excel to think that something is there. Any ideas on how I can get Excel to ignore the cells and graph only cells with actual values in them ?