Terri Vogel an amateur motorcycle racer averages 129 45 seconds per 2 5 mile lap in a 7 lap race with a standard deviation of 2 25 seconds The distribution of her race times is normally distributed We are interested in one of her randomly selected laps Source log book of Terri Vogel Let X be the number of seconds for a randomly selected lap Round all answers to 4 decimal places where possible a What is the distribution of X X N 129 45 2 25 b Find the proportion of her laps that are completed between 127 48 and 129 69 seconds 0 3518 c The fastest 3 of laps are under d The middle 60 of her laps are from seconds seconds to seconds