Consider the scenario in the screen shot below:

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Here we want to randomly display only one of the three images to the respondents. Requirements: In the above example Q1 and Q2 are general questions to be displayed to all respondents. The questions Q3, Q4 and Q5 are to be randomized and only 1 question is to be displayed to the respondents. The Survey should then go to the Thank you question. Steps for setting this up are:

Setup the entire survey with all the questions

Click on the Add New Question link for Q2 i.e. the question immediately before the first question that is to be added to the Randomizer

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Add the Randomizer question from the Advanced Questions menu

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Now first, add all the questions (Q3, Q4 and Q5 in the above example) that you want to randomize to the Randomizer

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In the Randomizer select the "Randomly Choose One question and display it" option

Select the Block Termination Question which in the above case is the Thank you Question

Click on the Save button to save the settings

Now click on the Done button to save the Randomizer

5. Screenshot

The above steps will only setup the Randomizer. Now for the Randomization to work you also need to point each question in the Randomizer to the Block Termination question.

Setup the default branching for Q3, Q4 and Q5 to branch to the Block Termination Question. This is a necessary step!

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Make sure you follow each and every step in order. To Recap:

Set up all the Survey Questions

Add the randomizer before the set of questions you want to randomize

Add all the questions to be randomized to the Randomizer

Select the "Randomly Choose One question and display it" option, select the Block termination question and save the settings

Save the Randomizer

Branch all the questions that need to be randomized to the Block Termination question

Can I set up Randomization within Randomization?

No. Currently Randomization within Randomization is not possible. You can have multiple Randomizers in the survey however, they shouldn't overlap.