# What are the right values for the prior mean and prior variance matrix in choice design?

I am doing my first choice experiment with JMP & the tutorial I found at http://blogs.sas.com/content/jmp/2009/01/15/optimal-design-of-the-choice-experiment/

Right now I am not sure if I understood everything correct. The author describes how to do the parameterization for an attribute with 3 levels:

"When there are three levels in increasing utility order, enter negative, then 0."

1. But what if I have e. g. 4 levels as it is the case for the attribute battery life?. (I think I need to define the prio means in the range from 1 until -1.)

2. Why did the author decide to use a range from -1 until 1? Why did he not choose any other range like -2 to 2 or -4 to 2?

3. Should I use different ranges for attributes? E. g. the range -1 till 1 for the attribute price, -2 till 2 for the attribute speed and for all other attributes use the range -1,5 till 1,5?

4. Every level in the prior variance matrix is 1.000. Is this because the range for the prio mean is between -1 and 1?

5. In the example below I did not specify any direction for the attribute brand. The prio variance matrix for brand 1 and brand 2 is also 1.000. Is this correct?

6. Final question :-) Does my first choice design have any issues that terrible scares you?