A fast food restaurant manager claims that they have an average time of 4.2 minutes with a standard deviation of 1.3 minutes as the duration between a customer entering the restaurant and the food being served to them. Brandon visited the restaurant every day and disagrees with the information provided by the manager. To check this, Brandon conducted a survey by selecting a random sample of 42 customers from the restaurant. He discovered an average time of five minutes from his sample and he calculated the probability of the average time until a customer is served will be at least five minutes. What conclusion should Brandon make based on his findings?