A couple months ago I was really excited to update my laptop from Ubuntu 17.10 to the newly released 18.04. A side affect of the upgrade was as I typed, my palms would inadvertently select things on the screen and remove focus of what I was actually doing. So I searched and made some changes based on what I read here: https://help.ubuntu.com/community/SynapticsTouchpad but the problem I had was that I don't really feel comfortable randomly changing configurations without actually knowing what I was changing. For instance, Synaptics Finger (267): 50, 80, 257 is great to know that those number will help me out, but what exactly does each value actually change. So I decided to look into a better explanation, which brought me to this page: https://unix.stackexchange.com/questions/28306/looking-for-a-way-to-improve-synaptic-touchpad-palm-detection While it still has config changes in it, at least I feel a little bit more comfortable with named values I'm changing. So I modified PalmMinWidth to equal 4 and then after a few iterations changed PalmMinZ to equal 75. These settings seem to have taken care of my problem for now. But I wanted to document what worked for me as to hopefully help others in the future.
On my setup, to persist the changed values, I had to add the following to the /usr/share/X11/xorg.conf.d/70-synaptics.conf file:
Option "PalmMinZ" "75"
Option "PalmMinWidth" "4"