What does "chance deviation" and "hits" mean in the following experiment?

What does "chance deviation" and "hits" mean in the following experiment? By the way, this excerpt is from Carl Jung's "On Synchronicity.""He used a pack of 25 cards divided into 5 groups of 5, each with its special sign (star, square, circle, cross, two wavy lines), The experiment was carried out as follows. In each series of experiments the pack is laid out 800 times, in such a way that the subject cannot see the cards. He is then asked to guess the cards as they are turned up. The probability of a correct answer is 1 in 5. The result, computed from very high figures, showed an average of 6.5 hits. The probability of chance deviation of 1.5 amounts to only 1 in 250,000."