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Posted By: John S

Actually, a sample size of 20 or above for each grouping (PSA 8 and raw VG's) would be sufficient to test significance. Using a t-test to compare averages (total width of all four borders on each card) between two groups would be the simplest and most powerful test in this case. Set the p-value at .05. Accurate measurements are a must...probably using a caliper of some kind. I believe that a board member has already made these types of measurements...cannot recall who that was.

The t-tests can now be done with most Excel programs.

Nice thought Joann.