random item selection

[ytgu]

Hi!

I wonder if FF allows us to randomly select from a pool of sentences and administer them to each subject?

For example, for Block A & Block B, we have 36 items in total, and we'd like the program to randomly administer 12 sentences (6 go to Block A, 6 go to Block B, and we don't want repetition within these randomly chosen 12 sentences). 

Please let me know if any of this doesn't make sense to you!

Thank you so much,
Yuting

[Ting]

Hi Yuting - sorry I just had a new baby and wasn't monitoring the forum. I'll ask the team to respond soon!

[mt_FF]

Hi Yuting,

I'm Maho, a member of the researcher experience team. Can I ask what the structure of Block A and B looks like and why you want to separate them, especially if you want to pull items from the same pool for the two blocks? If you can do with one block, you can add "stimulus_pattern": {"order": "random", "limit": 12} to your trial template in order to randomly pull 12 items from the pool for each participant. If you need to have two blocks and you don't want the items in the blocks to overlap, you can also split the 36 items into two sets, one for Block A and the other for Block B, and add "stimulus_pattern": {"order": "random", "limit": 6} for each.

Please let us know if you have any follow-up questions.

Best,
Maho

[ytgu]

Hi Yuting - sorry I just had a new baby and wasn't monitoring the forum. I'll ask the team to respond soon!

Congratulations Ting!!!  

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Hi Yuting,

I'm Maho, a member of the researcher experience team. Can I ask what the structure of Block A and B looks like and why you want to separate them, especially if you want to pull items from the same pool for the two blocks? If you can do with one block, you can add "stimulus_pattern": {"order": "random", "limit": 12} to your trial template in order to randomly pull 12 items from the pool for each participant. If you need to have two blocks and you don't want the items in the blocks to overlap, you can also split the 36 items into two sets, one for Block A and the other for Block B, and add "stimulus_pattern": {"order": "random", "limit": 6} for each.

Please let us know if you have any follow-up questions.

Best,
Maho

Hi Maho,

Thank you for the response! 

Our design is that we'll have 7 blocks in total, where each block contains 6 audio stimuli. Block A is the starting block, Block B is the finishing block. What we want the program to realize is to randomly select 6 sentences for Block A, and 6 sentences for Block B from all 36 sentences we have. The 12 sentences randomly pulled out from the 36 stimuli pool should not repeat within subjects. 

It sounds like based on your response, we could only split the 36 sentences into 2 lists (18 stimuli per list) and randomly pick 6 out of the 18 right? In other words, we couldn't randomly pick 12 (6 for each block) out of the 36 while also guarantee that there's no sentence repetition within subjects? Please correct me if I'm wrong! 

Appreciate your help.
Yuting

[mt_FF]

Hi Yuting - sorry I just had a new baby and wasn't monitoring the forum. I'll ask the team to respond soon!

Congratulations Ting!!!  

---

Hi Yuting,

I'm Maho, a member of the researcher experience team. Can I ask what the structure of Block A and B looks like and why you want to separate them, especially if you want to pull items from the same pool for the two blocks? If you can do with one block, you can add "stimulus_pattern": {"order": "random", "limit": 12} to your trial template in order to randomly pull 12 items from the pool for each participant. If you need to have two blocks and you don't want the items in the blocks to overlap, you can also split the 36 items into two sets, one for Block A and the other for Block B, and add "stimulus_pattern": {"order": "random", "limit": 6} for each.

Please let us know if you have any follow-up questions.

Best,
Maho

Hi Maho,

Thank you for the response! 

Our design is that we'll have 7 blocks in total, where each block contains 6 audio stimuli. Block A is the starting block, Block B is the finishing block. What we want the program to realize is to randomly select 6 sentences for Block A, and 6 sentences for Block B from all 36 sentences we have. The 12 sentences randomly pulled out from the 36 stimuli pool should not repeat within subjects. 

It sounds like based on your response, we could only split the 36 sentences into 2 lists (18 stimuli per list) and randomly pick 6 out of the 18 right? In other words, we couldn't randomly pick 12 (6 for each block) out of the 36 while also guarantee that there's no sentence repetition within subjects? Please correct me if I'm wrong! 

Appreciate your help.
Yuting

Hi Yuting,

Thank you for your clarification! And yes, if it's possible to split the 36 sentences into 2 lists, that's the best way to make sure that no sentence appears in both Block A and B for a participant. As long as you're pulling from the same stimulus pool for both blocks, the same item can get pulled twice. Hope it helps!

Best,
Maho