How can I implement a branching condition?

Question

I have a set of 31 questions but the respondant will just answer five of them. Depending on which answer option he chooses, he should jump to the corresponding defined question for this answer. Can I implement this with a filter-function or do I have to use PHP or Java?

Thank you so much for your help!

Example (Streamelined Model for Measuring Economic Preferences, Dohmen et. al)
Please imagine the following situation: You can choose between a sure payment
and a lottery. The lottery gives you a 50 percent chance of receiving 300 Euro.
With an equally high chance you receive nothing. Now imagine you had to choose
between the lottery and a sure payment. We will present to you five different situations.
The lottery is the same in all situations. The sure payment is different in
every situation.

1. What would you prefer: a 50 percent chance of winning 300 Euro when at the
   same time there is 50 percent chance of winning nothing, or would you rather
   have the amount of 160 Euro as a sure payment?
   (a) lottery --> go to question 17
   (b) sure payment --> go to question 2

2. What would you prefer: a 50 percent chance of winning 300 Euro when at the
   same time there is 50 percent chance of winning nothing, or would you rather
   have the amount of 80 Euro as a sure payment?
   (a) lottery --> go to question 10
   (b) sure payment --> go to question 3

.....

Answer 1

Can I implement this with a filter-function or do I have to use PHP or Java?

The filter conditions that can be defined within a question allow jumping in the questionnaire. For your application, however, it seems much more sensible to put the alterantive question on the same page and hide one of them - depending on the answer.