Why is HIV infection difficult to cure, even with treatment with multiple medications?

Glaucoma is an eye disease that is manifested by high intraocular pressure (iop). the distribution of iop measurements in the general population is approximately normal with mean 16 mm hg and standard deviation 3 mm hg. a random sample of 9 people is selected from the general population. the sample mean iop is 17.2 mm hg with a sample standard deviation of 3.9 mm hg. a) the mean of the sampling distribution of x is 16 mm hg. b) the standard deviation of the sampling distribution of x is 1.3 mm hg. c) the sample mean of every sample of size 9 will be 17.2 mm hg d) none of the answers are true. e) exactly 2 of the answers are true.

A46-year-old man with a history of hypertension and hypercholesterolemia visits the physician for a routine followup. the patient's job involves a lot of travelling, and he admits to occasionally forgetting to take his medications with him when he travels. he complains of several episodes of chest pain in the past few months. the pain is sharp in nature, mainly over his lower chest and epigastrium, and tends to come on when walking. he believes these episodes are due to indigestion and has been taking antacids. there is a family history of heart disease, and his father died of a heart attack at age 48. on physical examination, his blood pressure is 150/80 mmhg and heart rate is 86/min. his lungs are clear to auscultation. cardiac auscultation reveals normal rate and rhythm, without rubs, gallops, or murmurs. there is no pedal oedema. he is sent for an exercise stress test. five minutes into the test, he develops st depression of 3mm in leads v1-v5. the st segment depression is greater than 0.12 seconds in duration and the stress test is stopped. which of the following is the most appropriate next step in management? - coronary angiography- holter monitor- no further tests are required- repeat stress test with thallium- upper gastrointestinal endoscopy

Can someone give me a hand with this one.