Sensory memory in humans is very short-term and lasts approximately 200–500 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 l = 0.003. A flashing grid of letters is displayed to a randomly selected adult and the sensory memory is measured.
a. What is the probability that the sensory memory will last for at most 200 milliseconds
b. Find the median time the sensory memory will last.
c. Find a time t such that only 5% of all adults’ sensory memory lasts at least t milliseconds
Suppose X is an exponential
In the advertising department of SBC Communications, Inc., all of the computers are part of a local area network, connected to one main printer. When an advertising employee prints a document, the job is placed in a queue. It may take several minutes before the document begins to print, due to the number of other print jobs and the complexity of the document. The time (in minutes) until the document starts to print has an exponential distribution with l 5 0.40. Suppose a randomly selected document is sent to the main printer.
a. What is the mean time until the document begins to print?
b. What is the probability that the document will begin to print within 30 seconds?
c. What is the probability that the document will need more than 5 minutes before starting to print?
d. Find a value t such that only 2% of all documents take at least t minutes before starting to print.