Does "Random" mean "Random without replacement"?

[David McFarlane]

JB,

Yes.  In E-Prime, "Random" means "Random without replacement".  This 
is mentioned, among other places, in Tutorial 1 of the Getting 
Started Guide, and the RandomOrder Object topic of the E-Basic online 
help.  By contrast, "Random with Replacement", does, well, random 
with replacement.

But you should test this for yourself.  Make a simple test program 
with a single list of, say, 3 or 10 levels.  Set it to Sequential and 
make sure that it plays everything in order.  Set it to Random and 
see that it always does each level exactly once before 
repeating.  Set it to Random with Replacement and see that levels may 
repeat any time.

-- David McFarlane, Professional Faultfinder


At 6/26/2008 05:39 PM Thursday, you wrote:

>I'm setting up an experiment that displays varying amounts of blocks
>at random locations on the computer screen, as well at varying
>presentation durations. I should say that there must be an easier way
>to set this project up, but while I'm fairly adept at programming in
>eprime, I've never been too keen on InLine objects or User Script
>programing, so basically I know no other way than the fairly drawn-out
>point and click method (which amounts to many lists and a huge
>structure).
>
>Anyhow, the experiment consists of a number of lists all feeding off
>of one "master" list. Basically, at the "master" list, the program
>picks one of three procedures to cycle through, then returns to the
>"master" and cycles through again, randomly. I've weighted each of the
>three procedures in the "master" list so that they are all completed
>the same number of times, but my question arises after the program
>picks a procedure from the "master" list and begins to cycle through
>it... Once the "master" list randomly chooses one of the three
>procedures to cycle through, it meets a second list (actually, each of
>the three aformentioned procedures from the "master" list are set up
>this way, so you only need to imagine one... the answer will apply to
>all three). The second list consists of 11 different procedures that,
>in the end, display a series of blocks a different number of times at
>different presentation durations. It is important that all 11
>procedure types from List2 (i.e. displays/presentation durations) are
>presented an equal number of times. The second list is also set to
>select randomly, and set so that 1 cycle equals 1 sample. Herein lies
>my question:
>
>Currently each procedure in my "master" list is weighted at 11 so that
>it has the opportunity to display each of the 11 procedures from the
>second list... By setting my second list to "random", will eprime stop
>choosing a procedure that it has already chosen in a previous
>iteration of the program? In other words, after one of the 11
>procedures is chosen at random from List2, and the program cycles back
>to the "master" list to cycle through again, can/will the same
>procedure that has been displayed on a previous iteration be chosen
>again, or will the program not re-choose an "already chosen" procedure
>to run? With my project set up in this manner, can I be sure that all
>11 procedures from list 2 have been displayed, or should I be
>concerned that some may or may not ever be selected?
>
>I appreciate your help!
>
>jb


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