The weights of packages processed by a delivery company are normally distributed with a mean of 321 grams and a standard deviation of 20 grams. (a) Find the probability that the weight of a randomly selected package is less than 290 grams. Correct your answer to 4 decimal places. (4 marks) (b) Suppose the probability that a randomly selected package weighs more than im grams is 0.0314. Find the value of m. Correct your answer to 1 decimal place. (4 marks) () Suppose 4 packages are selected randomly. Find the probability that the average weight of the 4 selected packages is between 310 grams and 335 grams. Correct your answer to 4 decimal places. (4 marks) (d) Suppose the 75th percentile of the standard normal distribution is 0.67. Find the 75" percentile of the weights of the packages processed by the delivery company. Correct your answer to I decimal place. (2 marks)