According to the contingency table, K2 = 20× (5×10-2× 3) 28×12× 7×13 ≈ 4.4 > 3.841,
Therefore, according to the data of this spot check, under the premise that the error probability does not exceed 0.005, it can be considered that excellent physical performance is related to excellent mathematical performance;
(2) The number of people to be sampled is no more than 3, in which the sampling times are 1, 2,3, so the probability is14+34×14+(34) 2×14 = 3764.