A piano has 88 keys. Show with numbers the probability of hitting a particular key if you shut your eyes and strike one key?

The actual result of this scenario would change depending on how much you simplify it. If you were to simply regard each key as having an equal probability of being struck, then you could say that each key has a 1/88 chance of being hit. That is, statistically speaking, if you were to hit the piano randomly 88 times you should hit each key once. However, this is probably not true in real life. From the vantage point you have over the piano, you are situated more comfortably over the middle range of keys. So this means that you will be more likely to hit those within your range of motion. Another facet to this is the predictability of human nature. Knowing that they will be expected to hit the keys that lie closer to them, the general person will deliberately reach out and hit a key further away from them to 'make it look random'. Contrary to their intent, this actually alters the probability of hitting the other keys, biasing the experiment.