Fourteen tomato plants of similar height and age were chosen at random from a greenhouse. Seven of these, chosen at random from the 14, were treated with a chemical to enhance growth rate. The other seven were not treated. After two weeks, the height of each plant was measured. The height gains in mm of each plant were recorded as Treated: 25, 45, 36, 11, 41, 29, 38, (mean: 32.1 and standard deviation: 11.6) and Untreated: 32, 18, 8, 29, 17, 11, 11 (mean: 18 and standard dev. : 9.3). Assume normal distributions. Does the treatment result in a growth rate change ? (6 marks)

2) You later learn that the data in problem 1 are drawn from populations with non-normal distributions. Does the treatment result in a different growth rate ? (6 marks)