From his long-standing experience, a farmer believes that the mean yield of grain per plot in his farm is 160 bushels. When a new seed introduced on the market was tried on sixteen randomly selected experimental plots, the mean yield was 168 bushels. Suppose the yield per plot can be assumed to be normally distributed with a standard deviation of yield of 22 bushels. Is the new seed significantly better? Use 0.05 as the level of significance.