A primary factor in the operating speed of a personal computer is the clock speed of its microprocessor chip. The manufacturer claims a speed of 1.0 MHZ with a standard deviation of 1.2 MHz. We randomly sample 70 chips.
What is the probability that their sample mean is between 0.7 and 1.3 MHz?
What is the probability that their sample mean is more than 0.8 MHZ?