text: As you can see, we've fixed our balance problem. Now each attribute level appears the same number of times. And, if you look at the example questions, at least the same attribute level is not appearing twice. Do we have a good design now? Have a look at the questions. No, it's not a good design.
  The second question's just a bit silly. Who will choose the General Motors car at twice the price of the Ferrari? You could just get the Ferrari and resell it to buy a lot of GM cars.
  One fix is to prohibit certain alternatives from appearing. This is called using prohibitions. Now, you might be thinking. Cool. Problem solved. But, it's not so simple. To explain why I need to introduce a new concept.
  If we look in the top right we can see that Displayr is giving us a warning. It says we should either change the design or change the sample size to get a big enough sample.