Two new anti-inflammatory drugs (drug A and drug B) were randomly administered to patients with chronic

inflammatory diseases admitted to a local hospital. The C-Reactive Protein (CRP), measured in milligram

per liter (mg/L), from their blood sample are given in the table below. A higher CRP level indicates more

severe inflammation. You may assume the CRP levels are normally distributed.

drug A 7.7 7.0 7.2 8.9 6.8 8.6 8.0 6.5 6.8 9.0

drug B 9.6 8.1 10.4 9.7 9.6 8.7 11.1 9.9 10.2 10.2

Table 1: C-reactive protein (CRP) level (in mg/L) of 20 patients in an anti-inflammatory drugs trial.

(a) Is the variance of CRP level significantly different between the group of patient administered with

drug A and the group administered with drug B? Perform a statistical test for the equality of the

variances at = 0.05 level of significance. State the null and alternative hypotheses, test statistic,

critical region, and your conclusion.

[5 marks]

(b) Assuming the patients have similar CRP levels prior to taking the drug, is drug A more effective

than drug B in lowering CRP levels? Perform an appropriate statistical test, using = 0.05 level of

significance. State the null and alternative hypotheses, test statistic, critical region, and your conclusion.

[5 marks]