Re: [ATM] figure stroke ten inch

[Jim Burrows <burrjaw@earthlink.net>]

Tom Fredrickson wrote:

New readings:  0, 0.91, 1.36, 1.93, 2.15

Be careful!  Maybe you're done.  Sixtests says surface RMS = 19.1 nm, 
Strehl ratio 0.827, which is passing.  If you approach the mirror 
with a pitch lap, only do 2-3 minute spell.  Maybe before that, do 
another Foucault test with multiple readings to confirm that your 
reading sigma (standard deviation) is really 0.01 mm as I assumed 
from the last digit in your posted readings.  If the 0.01 is right, 
Sixtests says the RMS sigma is 3.1 nm, implying the 20 nm requirement 
isn't outside the 2 sigma confidence interval (that all statisticians demand).

         -- Jim Burrows
         -- http://home.earthlink.net/~burrjaw
         -- mailto:burrjaw@earthlink.net
         -- Seattle N47.4723 W122.3662 (WGS84)


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