A livestock company reports that the mean weight of a group of young steers is 1171 pounds with a standard deviation of 86 pounds. Based on the model N(1171,86) for the weights of steers, what percent of steers weigh a) over 900 pounds? b) under 1250 pounds? a) % of steers have weights above 900 pounds. (Round to one decimal place as needed.) b) % of steers have weights below 1250 pounds. (Round to one decimal place as needed.)