A certain kind of automobile battery is known to last average of 1130 days with standard deviation of 150 days. If 900 of these batteries are selected, determine the following probabilities for average length of life of the selected batteries. (Round your answers to four decimal places.)
(a) The average is between 1120 and 1130.
(b) The average is greater than 1140.
(c) The average is less than 950.