A manufacturer wants to increase the shelf life of a line of cake mixes Past records indicate that the average shelf life of the mix is 216 days. After a revised mix has been developed, a sample of nine boxes of cake mix gave these shelf lives (in days) 215, 217, 218, 219, 216, 217, 217, 218, and 218. Using a = 0.025, has the shelf life of the cake mix increased? Yes, because computed t is greater than the critical value. Yes, because computed tis less than the critical value. No, because computed tlles in the region of acceptance. O No, because 217.22 is quite close to 216