Using jsPsych.randomization.sampleNormal

[fspinar]

Hey all,

I am trying to use jsPsych.randomization.sampleNormal function, but I get the following error:

Uncaught TypeError: jsPsych.randomization.sampleNormal is not a function

I am using version 6.3 Could this be because this function is introduced in a later release?

I just want to do

x = jsPsych.randomization.sampleNormal(mean,std);

Thanks a lot !

[jodeleeuw]

This function was added in version 7.1, so you would need to upgrade to use it.

However, this is a pretty small function to just add to your project. This function, from this StackOverflow answer, will generate a random sample from a normal distribution with mean 0 and standard deviation 1.

// Standard Normal variate using Box-Muller transform.
function randn_bm() {
    var u = 0, v = 0;
    while(u === 0) u = Math.random(); //Converting [0,1) to (0,1)
    while(v === 0) v = Math.random();
    return Math.sqrt( -2.0 * Math.log( u ) ) * Math.cos( 2.0 * Math.PI * v );
}

If you want to be able to set the mean and std then this will let you do that:

function sampleNormal(mean, standard_deviation) {
  return randn_bm() * standard_deviation + mean;
}