A student conducts a lab exercise to calculate the acceleration of gravity, g, and gets a value of 9.5 m/s^2 with a standard deviation of 0.1.The student knows that the answer at his altitude and earth coordinates should be 9.8 m/s^2 . What is the probability of getting this result due to random chance (random error) alone? Neglecting outright blunders (he is a careful experimenter), comment on a possible cause for the result.