OBJECTIVE FORESTRY

A noted psychic is tested for extrasensory perception. The psychic is presented, one at a time, with cards that are marked with one of four symbols:a star, a cross, a circle, or a square. Let p represent the probability that the psychic correctly identifies the symbol on the card in a random trial. Which of the following is the smallest number of trials you would have to conduct to estimate p to within ± 0.01 with 95% confidence? (Use the guess 0.25 as the value for p, since this would be the value of p if the psychic were merely guessing.)