Question

I have a model like so:

class RunnerStat(models.Model):
    id_card= models.CharField(max_length=32)
    miles = models.PositiveSmallIntegerField()
    last_modified = models.DateField(auto_now=True)

I want to create several RunnerStat instances with random miles values that average up to a specific number.

I know this might involve some statistics (distribution, etc.). Does anyone have any pointers? Or done something similar and could share some code?

Example: Create 100 RunnerStat objects with random miles values that average out to 10.

Answer 1

If the average has to be around the the given number but not exactly it you can use the random.gauss(mu, sigma) from the random module. This will create a more natural random set of of values that have a mean (average) around the given value for mu with a standard deviation of sigma. The more runners you create the closer the mean will get to the desired value.

import random

avg = 10
stddev = 5
n = random.gauss(avg,stddev)
for r in range(100):
  r = RunnerStat(miles=avg+n)
  r.save()

If you need the average to be the exact number then you could always create a runner (or more reasonably a few runners) that counter balance what ever your current difference from the mean is.