The lifespan of a car battery is approximately normally distributed, with mean equivalent to 4 years and a standard deviation of 5 years. What is the probability that a random sample of 25 car...

The lifespan of a car battery is approximately normally distributed, with mean equivalent to 4 years and a standard deviation of 5 years. What is the probability that a random sample of 25 car batteries would have an expected lifespan of
i) more than 6 years?
ii) at least 3 years but less than 7 years?