The steps below will help you discover whether or not you know the password to an admin account on your device...
Step 1 - Click the Apple Menu 
>> System Preferences:
Step 2 - Click on ‘Users and Groups’
Step 3 - Unlock the padlock using your computer password so that you can make changes.
Step 4 - IF you have an account called 'tests' or 'Tests', delete it using the minus (-) symbol under 'Login options'. IF YOU DO NOT have an account called 'tests' or Tests', move to step 5.
Step 5 - Note the name of an admin account that you normally use to log in to your computer. You should know the password to this account if you already use it to log in to your computer. If you do not have an admin account, your parents need to create one for you using these steps.
Step 6 - Lock the padlock to prevent any further changes.
Step 7: Restart your computer by clicking the Apple symbol >> 'Restart'. After your computer restarts, log in with the same admin account you noted in Step 5 (see below).
Step 8 - Log In with the same admin account that you noted in Step 3
If you can successfully log back into your computer, then you know the password to an admin account 
Now move on to phase 2 of the process: 'Downloading and Installing The Test Software'.