Two different alloys are being considered for making lead-free solder used in the wave soldering process for printed circuit boards. A crucial characteristic of solder is its melting point, which is known to follow a Normal distribution. A study was conducted using a random sample of 21 pieces of solder made from each of the two alloys. In each sample, the temperature at which each of the 21 pieces melted was determined. The mean and standard deviation of the sample for Alloy 1 were x1 = 218.9oC and s1 = 2.7oC; for Alloy 2 the results were x2 = 215.5oC and s2 = 3.6oC. Test at the 0.05 level of significance to determine whether the population mean temperatures of the two alloys differ. (20p) Tips: if the critical value is not given in the table, choose the value closest. Specify your choice of degrees of freedom clearly in your solution.