(9 marks) 1. A researcher is interested in examining the cholesterol levels of heart- attack patients. Cholesterol levels are measured for 28 heart-attack patients (2 days after their attacks) and 30 other hospital patients who did not have a heart attack. The researcher believes that cholesterol levels will be higher for the heart-attack patients. Random samples from each group provide the following results: Heart-A Heck Patients Non-Heert-A track Patients Sample Size 28 3111 Mean Cholesterol [mgfm 213.9 193.1 Standard Deviation of Cholesterol (mgf'DL) 4'1? 22.3 Assume that the cholesterol levels for both populations are normally distributed and that the population standard deviations are equal. Using a 5% signicance level, can the researcher conclude that the mean cholesterol level of heart-attack patients is greater than the mean cholesterol level of non-heart-attack patients? Formulate and test the appropriate hypotheses. State and explain your conclusion within the context of the question. Use the critical value approach