I mistakenly contributed to my Roth IRA for 2018. This was a mistake because our income is now too large to keep contributing to a Roth. I have since removed the excess. Can I now contribute instead to a Traditional IRA for 2018?
Yes, provided you were not age 70½ or over in 2018 and you have sufficient compensation to support the contribution (which, presumably you do, otherwise you probably would not have contributed to the Roth IRA originally).