Bar Chart with trend or average line (XY)

[overbomb]

Hi

I've created a graph from data and need to add an average/net impact/trend line to the graph. From what I've read this needs to be an XY scatter, however, several efforts later and I can't seem to get it to work for me

Would be very grateful if someone could offer some insight

Many thanks

Maddy

0514_Costs_DRAFT_ExcelF.xlsx

[Andy Pope]

You will not be able to add a built-in trend line to a stacked chart type.

You will not be able to add you own trendline plotted as a xy-scatter series whilst the chart type is a variation of 3d chart.
So first change chart type to stacked bar.

It's not clear exactly which data should be treated as the trend or average.