How can I plot envelope and medium line for data(x,y)?

Hello,

I am a novice to matlab, trying to create a graph with a lower and upper envelope lines and a medium line using data from two vectors, see attached variables .

The final graph I want to create should look like this

Thanks.

[Jan]

How is "envelope" defined? There is one point at x=0.6 outside the lines.

[Kelsey Dean]

My understanding from the paper is that lower envelope line should be for all points.

I am unsure why the authors did not place the 0.6 point within the lower enevelope lines, I have been assuming it was a mistake.