[esquire_900]

You make a good point, though I'd like to add that one would expect 1/365 = .274% of procedures to be on a random day (like a birthday). .21% is not so far off that it can't be random chance.

[eCa]

That, and since most planned surgeries ought to take place Mon-Fri, if anything it’s a higher percentage than I would have expected.

[Dylan16807]

Day of the week cancels out.

[ChrisLomont]

> .21% is not so far off that it can't be random chance

How far off exactly would it need to be before it can be random chance?

[esquire_900]

Interesting question, wondered that myself as well. My statistics are a little rusty, so doing a quick simulation shows that the range is about .25-.29 (code sample 1). However, things like operations aren't completely random, and you might be more correct by looking at something like a Poisson process, resulting in a range of about .14-.44 for this sample size (code sample 2).

All in the end to be taken with a grain of salt of course, as the planning component of operations eliminates most statistical properties :)

``` operations = np.random.randint(0, 365, 980000) pd.Series(operations).value_counts().sort_values() / 980000 ```

``` x = np.random.poisson(.0089, 1000000) x = (pd.Series(x).cumsum() / 24).round() x.groupby(x).count().iloc[:365].sort_values() / 980000 ```