I'm a student completing a project and at this point, I'm way over my head, never used ArcGIS or much of anything data science-y, so I'm really struggling. I'm using census data to create a map of Chicago community areas colored from highest to lowest rate of occurrence, I have the data in excel and have assigned conditional formatting to it, creating a color scale for each community area, now how do I assign a style to the map so that I don't have to handpick hex codes for all 77 areas?
This is very vague but I'm not sure how to explain it better.
Have you tried using counts and amounts and then pointing it to your rate field? In the example below my rate field is % Housing Units Occupied. To further specify colors and ramp settings, click Style Options:
If you're still stuck, seeing a screenshot might help to further address your question.
So I have, for example, disability per capita for each of the community areas, I just would have to know how to add that as a field, probably within the geojson file of community areas, and I'm not sure how to do that, at least not efficiently.
It sounds like the field you want to symbolize on isn't yet a field, but provided you can calculate it using existing fields in your layer, you can do this directly in the web map symbology.
Click "+ Expression" at the top under "Choose Attributes". From there, you calculate the disability per capita which you can then symbolize on.
This storymap describes an example, see the Rate section:
https://storymaps.arcgis.com/stories/e5c8528325c84d56b24afddaa796bfac