The weights of a fish in a certain pond that is regularly stocked are considered to be normally distributed with a mean of 3.1 pounds and a standard deviation of 1.1 pounds. A random sample of size 30 is selected from the pond and the sample mean is found to be 2.4 pounds. Is there sufficient evidence to indicate that the mean weight of the fish differs from 3.1 pounds? Use a 10% level of significance.