A post relating to a political issue is going around saying it is astronomically unlikely that 7 hard drives would crash in the same month, specifically:
The odds of a disk drive failing in any given month are roughly one in 36. The odds of two different drives failing in the same month are roughly one in 36 squared, or 1 in about 1,300...37 to the 7th power = 1 in 78,664,164,096.
My first reaction was that the proper odds would relate to 7 out of N and, in an organization, N is likely to be much larger than 7. OTOH, if the claim is a specific mail server and it's backup, N = 7 might make sense.
Unfortunately, at this point, my Google-fu cannot penetrate the echo-chambering of the "astronomical odds" post to know what has actually been claimed in terms of hard drive failure.
Also, to use (1/36)^7, the odds of drives crashing would have to be independent, which I think could be relevant if the claim of data loss relates to a RAID configuration (?).
I am skeptical that the IRS made the claim for which the post's math would be appropriate (i.e., I am skeptical that the IRS said 'the loss of email was due to the specific failure of 7 out of 7 independent drives'). As dmckee put it in comments: "[I am] asking what the IRS is actually claiming about hard drive failures that might be preventing them for complying with congressional requests for information about some [high politicized event that shouldn't play any part in the answers]."
P.S. I've had trouble finding appropriate tags for this question.