You can't run the beta unless you have the released version installed.
But you need to be aware that the beta and release versions do not share Preferences, brushes, styles, or any other resources. So anything (like brushes) that you import into the beta will have to be reimported into the release version later. And any preference changes you make will need to be redone. And so on.
You may also find that files created with the beta version can't be opened with the older release version; e.g., 1.7.2 may not be able to open 1.7.3 files, or make use of anything saved in 1.7.3.
