Wednesday 28 April 2021

Do March's lead articles obey Benford's Law? And how does the running total look?

 This is the results of the second month of monitoring news articles for which numbers they contain.

March featured the first days I missed (I blame Easter), so I will have to add two days on at the end of the year.

In the 29 days I did manage to capture, 273 numbers were used (~ 9 to 10 per day).  This is less than the ~15 per day from February.


1 and 8 are the closest to expected.  5 is over-represented. If you add together the sum of all the values of (observed-expected)squared, all divided by the expected, the calculated test statistic is 5.6.

The critical chi squared value for 9 items with only one line is ~ 15.507

The test statistic smaller than the critical value therefore the difference is not significant. This data does not disobey Benford's Law.

If you look at the rolling total of February and March, the numbers are starting to add up.  There were 709 digits in headline news articles.


7 and 8 are the closest to expected.  1 remains over-represented, as it was in February. If you add together the sum of all the values of (observed-expected)squared, all divided by the expected, the calculated test statistic is 3.49.

The critical chi squared value for 9 items with only one line is ~ 15.507

The test statistic smaller than the critical value therefore the difference is not significant. This data does not disobey Benford's Law.

Interestingly, as more numbers from articles have been added the calculated test statistic has reduced (February = 8.6, February + March = 3.49).  This is what you would expect to see if the numbers in the articles fulfill Benford's law.

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