I have been reading up on probability a bit. Most of the time the type of distribution used is provided but sometimes the question seems rather ambiguous. In such cases how do you go about determining which distribution to use?
A soft drink vending machine is set in such a way that the amount of drink dispensed is a random variable with a mean of 200 millilitres and a standard deviation of 15 millilitres. What is the probability that the average amount dispensed in a random sample of size 36 is at least 205 millilitres?
My intuition says I should go with normal distribution.