Question 4 [10 marks] Sensory memory in humans is very short-term and lasts approximately 20% 500 milliseconds after an individual perceives an object. Suppose the length of time (in milliseconds) an object remains in sensory memory for a randomly selected adult has an exponential distribution with )1 = 0.003. A ashing grid of letters is displayed to a randomly selected adult and the sensory memory is measured. a. [3 marks] What is the probability that the sensory memory will last for at most 200 milliseconds? b. [3 marks] Find the median time that the sensory memory will last. c. [4 marks] Find a time such that only 5% of all adults' sensory memory lasts at least tmilliseconds