Median line on scatter chart

[#1]

How can i add 1 line of median into the scatter chart below?izzit possible??

I hope to get the result shown as below. The median line can across all the point but the remainded point should be there also....

[whiteline]

Hi.

Properties -> Presentation tab -> Reference Lines -> Add -> Type expression and choose the axis.

[#3]

This is what i did.....but still unable to add the median line...izzit my wrong??

[whiteline]

Hi.

The reference line is always horizontal.

Use trendlines feature on expression tab if you want to show linear regression.