Millisecond Forums

randomly splitting item into two

https://forums.millisecond.com/Topic29254.aspx

By anisa_khalfan - 6/16/2020

I have an item with 14 foods, and I want to randomly divide half into an item called natural_condition and the other half into an item called health_condition each time a participant runs the experiment. Is there a function that lets me do this? I have attached the item code below. 
Thanks in advance.

<item foodpic>
/1 = "Cheetos_4_25pc.jpg"
/2 = "Aero_2_.5bar.jpg"
/3 = "Twizzlers_3_4.jpg"
/4 = "TeddyGrahams_2_15pc.jpg"
/5 = "Snickers_1_0.5bar.jpeg"
/6 = "Skittles_4_0.25pack.jpg"
/7 = "ChipsAhoy_4_2cookies.jpg"
/8 = "RitzBits_4_15pieces.jpg"
/9 = "RufflesAllDressed_3_10chips.jpg"
/10= "Smartfood_3_32Chips.jpg"
/11 = "Spinach_2_.5c.jpg"
/12 = "Orange_2_0.5orange.jpg"
/13 = "GreenGrapes_3_12.jpg"
/14 = "BrusselsSprouts_3_0.5box.jpg"
</item>
By Dave - 6/16/2020

 
anisa_khalfan - 6/16/2020
I have an item with 14 foods, and I want to randomly divide half into an item called natural_condition and the other half into an item called health_condition each time a participant runs the experiment. Is there a function that lets me do this? I have attached the item code below. 
Thanks in advance.

<item foodpic>
/1 = "Cheetos_4_25pc.jpg"
/2 = "Aero_2_.5bar.jpg"
/3 = "Twizzlers_3_4.jpg"
/4 = "TeddyGrahams_2_15pc.jpg"
/5 = "Snickers_1_0.5bar.jpeg"
/6 = "Skittles_4_0.25pack.jpg"
/7 = "ChipsAhoy_4_2cookies.jpg"
/8 = "RitzBits_4_15pieces.jpg"
/9 = "RufflesAllDressed_3_10chips.jpg"
/10= "Smartfood_3_32Chips.jpg"
/11 = "Spinach_2_.5c.jpg"
/12 = "Orange_2_0.5orange.jpg"
/13 = "GreenGrapes_3_12.jpg"
/14 = "BrusselsSprouts_3_0.5box.jpg"
</item>

You do something like this:

<list allitemnumbers>
/ poolsize = 14
/ selectionrate = always
</list>

// item numbers we'll use in the health condition
<list healthitemnumbers>
</list>
// item numbers we'll use in the natural condition
<list naturalitemnumbers>
</list>

// put 7 random item numbers out of 14 into the health list
// put the remaining 7 item numbers out of 14 into the natural list
<expt>
/ onexptbegin = [
    list.healthitemnumbers.appenditem(list.allitemnumbers.nextindex);
    list.healthitemnumbers.appenditem(list.allitemnumbers.nextindex);
    list.healthitemnumbers.appenditem(list.allitemnumbers.nextindex);
    list.healthitemnumbers.appenditem(list.allitemnumbers.nextindex);
    list.healthitemnumbers.appenditem(list.allitemnumbers.nextindex);
    list.healthitemnumbers.appenditem(list.allitemnumbers.nextindex);
    list.healthitemnumbers.appenditem(list.allitemnumbers.nextindex);
    
    list.naturalitemnumbers.appenditem(list.allitemnumbers.nextindex);
    list.naturalitemnumbers.appenditem(list.allitemnumbers.nextindex);
    list.naturalitemnumbers.appenditem(list.allitemnumbers.nextindex);
    list.naturalitemnumbers.appenditem(list.allitemnumbers.nextindex);
    list.naturalitemnumbers.appenditem(list.allitemnumbers.nextindex);
    list.naturalitemnumbers.appenditem(list.allitemnumbers.nextindex);
    list.naturalitemnumbers.appenditem(list.allitemnumbers.nextindex);
]
/ blocks = [1=myblock]
</expt>

<block myblock>
/ trials = [1-14 = noreplace(healthtrial, naturaltrial)]
</block>

<trial healthtrial>
/ stimulusframes = [1=healthpic]
/ validresponse = (57)
</trial>

<trial naturaltrial>
/ stimulusframes = [1=naturalpic]
/ validresponse = (57)
</trial>

<picture healthpic>
/ items = foodpic
/ select = list.healthitemnumbers.nextvalue
</picture>

<picture naturalpic>
/ items = foodpic
/ select = list.naturalitemnumbers.nextvalue
</picture>

<item foodpic>
/1 = "Cheetos_4_25pc.jpg"
/2 = "Aero_2_.5bar.jpg"
/3 = "Twizzlers_3_4.jpg"
/4 = "TeddyGrahams_2_15pc.jpg"
/5 = "Snickers_1_0.5bar.jpeg"
/6 = "Skittles_4_0.25pack.jpg"
/7 = "ChipsAhoy_4_2cookies.jpg"
/8 = "RitzBits_4_15pieces.jpg"
/9 = "RufflesAllDressed_3_10chips.jpg"
/10= "Smartfood_3_32Chips.jpg"
/11 = "Spinach_2_.5c.jpg"
/12 = "Orange_2_0.5orange.jpg"
/13 = "GreenGrapes_3_12.jpg"
/14 = "BrusselsSprouts_3_0.5box.jpg"
</item>