"Pass rate for Quiz" should be able to be blank

When creating a quiz, under "Quiz Summary Options", "Pass rate for Quiz (%)" probably shouldn't need input. If you don't enter anything, it would make more sense if it assumed "0", since the user doesn't want that feature.

If this isn't changed, then I recommend changing the help text for "Summary text if passed", because right now, it ends with the misleading:

If you don't use the 'Percentage needed to pass' field above, this text will not be used.

Also, the first field isn't called "Percentage need to pass" anymore (it's "Pass rate for Quiz"), but that's minor :)

Great work, by the way! Just thought I'd pass this on!