In the lesson we use the same sentence for each example to show that just the intonation alone can change how NO is used. But it is very easy to understand. When NO is said sounding like a question then that is what it is. If it doesn't sound like a question then it isn't and it is purely emphasis.
NO as a question can be used by male or female, HOWEVER the emphasis NO tends to be female or young child. In replacement of NO men would most likely use YO for there emphasis.
The best thing to do to figure this out is to rent some Japanese videos if you can in your area and watch how NO and YO are used. In Las Vegas there is a place right across from the Hard Rock Hotel called Video Japan that has tons are material you can practice with. If you don't have a place nearby then I recommend you purchase some Japanese dramas on video and watch those.
When I was learning Japanese, TV was my biggest influence and helped me the most in figuring out patterns and applying what I had learned.
I definetly think there is an error in this lesson. Not only are the same sound files used for the の as a question and の as an emphasis, but also the English translations underneath are exactly the same. So the の that is supposed to be emphasis is even shown as a question mark in the English translation. You might want to fix this.
There is an error in the grammar section of lesson 9. The NO as a question marker is really the exact same sound files as the NO for emphasis. The NO for emphasis even has a question mark after it. I believe the NO for emphasis section is actually exactly the same as the NO for a question marker section, which is confusing, and you don't get a feel for what the emphasis is supposed to sound like. So, I think it would be good to do some work on this lesson. Especially because none of the sound files work for YO either. I am posting this again because I do not think it got noticed last time, and I can't just copy and paste my old comment because of the way the sight works now.(protection policy, can no longer highlight and copy...)
Okay, well its good to hear the problem has been identified. I was so insistent about it because I thought it would be important to hear the differences in how the endings are said. I realize you are busy, so thank you.