3. The number of days since the appearance of a tumour in an animal, and the size of the tumour, are shown below: Days 14 16 19 21 23 26 28 30 33 Size(cm]) 1.25 1.90 4.75 5.55 7.53 14.5 16.7 20.9 27.1 Construct the best regression that you can find, and use the model to estimate the size of the tumour after 24 days. [25 marks] 4 (a) Test the hypothesis that the average dissolution time is 21 seconds, using the random sample of dissolution times below. Dissolution time (secs): 23 19 26 22 23 27 (b) Two different instruments were used to make a number of replicate measurements. The results were: Instrument A: 12.06 12.14 12.03 12.09 12.05 Instrument B: 14.62 14.97 14.60 14.51 14.01 14.11 Do these results indicate that either instrument is more precise? [25 marks] 5. Dissolution is compared for three experimental batches of tablets with the following results (each point is the time in minutes for 50% dissolution for a single tablet). Batch 1: 15 18 19 21 23 26 Batch 2: 13 10 16 11 9 Batch 3: 17 18 24 20 (i) Is there a significant difference between batches? (ii) Which batch is different? [25 marks]