How to Change the Default Calendar on an iPhone

You can change the default calendar in the iPhone Settings:

Navigate to Settings
Tap Mail, Contacts, Calendars
Scroll down to the Calendars section and set the Default Calendar to your @risd.edu account calendar.

When this might be needed:

User finds that their events created on iPhone are not syncing with their account or another calendar - Most likely their default calendar is set to another account, or to another iPhone default calendar. The user can either make it a point to check what calendar the event is being added to or they can change their default calendar.