statistics question

Question 21 4 pts Let x be a random variable representing dividend yield of Australian bank stocks. We may assume that x has a normal distribution with a = 2.1%. A random sample of 13 Australian bank stocks has a sample mean of x = 8.78%. For the entire Australian stock market, the mean dividend yield is / = 5.7%. Do these data indicate that the dividend yield of all Australian bank stocks is higher than 5.7%? Use