7. (12 points) Acid rain, caused by the reaction of certain air pollutants with rainwater, is a growing problem in Canada. Pure rain falling through clean air registers a pl value of 5.7. Note that pH is a measure of acidity: 0 is pure acid and 14 is pure alkaline. The smaller the pH. the more acidic the rain. The sample of n = 49 rainfalls in the Greater Toronto Area (GTA) produced pH readings with a - 5.5 and s = 0.7. Do the data provide sufficient evidence to indicate that the mean pl for rainfalls in the GTA is more acidic than pure rainwater? Test with a = 0.05. (a) Choose the correct null and alternative hypotheses. You do NOT need to justify your answer. (i) Ho : # = 5.7 against Ha : [ > 5.7 (ii) Ho : 1 = 5.7 against Ha : u # 5.7 (iii) Ho : p = 5.7 against Ha : H 5.7 (b) Compute the test statistic