I would like to know how can you describe this . 

2. Weights of Hong Kong Citizens are known to follow a Normal distribution with mean 127.081bs, and standard deviation 11.661bs. (a) Suppose you take a sample of 4 residents. What is the probability that the sample mean length of stay for this group is less than 125lbs? If you cannot calculate this probability, state so and state why. [2 marks] (b) Suppose you take a sample of 100 patients. What is the probability that the mean length of stay for this group is between 126 and 1281bs? If you cannot calculate this probability, state so and state why. [2 marks] (c) For each of the probabilities calculated above, state which are approximate, and which are exact, and state why. [2 marks]