penny%thickness%
A%histogram%of%the%
measured%thickness%of%
100%new%pennies%(which%
haven't%been%worn%
appreciably%and%should%
all%be%the%same%thickness)%
using%a%crude%
micrometer.%The%average%
thickness%for%this%sample%
is%1.42mm%and%the%RMS%
of%the%distribuEon%is%
0.07mm.%%
The%thickness%of%a%new%penny%is%designed%to%be%1.52mm,%considerably%thicker%than%
the%average%of%the%sample%above.%The%shiI%in%the%distribuEons%suggests%some%kind%of%
systemaEc%error%in%the%measurement.%In%this%case,%the%two%faces%of%the%micrometer%
are%not%exactly%parallel;%on%one%side%the%micrometer,%where%we%made%all%the%
measurements,%it%measures%a%liMle%too%low.%
