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2. Researchers believe that the concentration of a particular hormone is lower in subjects suffering from hypothyroidism (underactive thyroid gland) than subjects with normal functioning thyroid. The concentration of this hormone for a sample of 11 subject with hypothyroidism was measured and compared to the concentration measured in a sample of 17 subjects with normal functioning thyroid. The table below shows a summary of the two samples. s2 п Hypothyroid 4.1 2.3 11 Normal 5.2 1.2 17 (a) Is there evidence in favor of researchers' claim? State null and alternative hypotheses and use an appropriate test to test the claim. Use a signifi- cance level a = 0.05. [10 marks] = (b) What assumptions did you make in performing the test conducted in part (a) above? [4 marks] (c) Compute a 95% confidence interval for the difference in mean hormone concentration between hypothyroid and normal subjects. [6 marks]