Error: Insufficient privileges to write to MacPorts install prefix.

[Jim Mattingly]

Getting the above-referenced error code when attempting command: port install pspp, Have even tried sudo, although it is only a single-user computer at home, then sudo scolds me and asks for a password I don’t have. Downloaded Xcode from app store and macports, according to macports guide, and env command worked just fine, but both install and selfupdate commands tell me I don’t have the necessary privileges to run them. Simply running commands on apple terminal with Xcode open. Any ideas what to do? I’m perhaps a relatively advance user, but not an IT pro, so perhaps there is something simple I’m overlooking.