Graph in excel

Hello, this might not be a first time people ask this question, but here I a

My sample size is 400 Ph results of soil test. The data ranges from from 5.0 to 8.3. Ph of soil should be 6.0 to 7.0 for growing some crops. With the graph I would like to display number points that do not fall under optimal Ph range. What is the way to display graph in excel that shows data sets that deviate from Ph norms? i.e 6.0-7.0.

I was able to display data in scatter plot but wasn't able to set "boundary" that shows limits.


Thanks in advance folks,

Davron