Today is also National Nougat Day, so you have decided to make a batch of a tasty mix of nuts, dried fruit honey and sugar. You divide the mixture up into small balls in a pan, and decide to weigh each ball of nougat. You find that the balls weight an average of 120 grams, with a standard deviation of 10 grams. You decide to weight the nougat balls in groups of 15, and average the weights together. What would be the standard error for the weights, for a sample average of 15 balls? Assuming that the average weights of 15 balls at a time follows a normal distribution, what is the probability that the average weight of 15 balls is less than 115 grams