I was measuring a 10pF 0603 +-5% (Johanson 251R14S100JV4S) using a network analyzer at 319.5MHz. The cap came in their high q/low ESR ceramic kit.
It measured about 10.7pF. But after measuring a few more 10pF parts, I noticed the capacitance was either around 10.7pF, or 11.3pF, give or take .05pF. Even after checking a dozen or so, they were all grouped around 10.7 or 11.3. In other words, NONE were 10.9 or 11.1.
Any idea why? I know the nominal capacitance is different at frequencies other than their test frequency, but I guess I expected them all to center around some value and be randomly sprinkled within 5%.