Applied Engineering Statistics Exam Exam Date：April 26，5pm-7pm, (UTC+8), Please notice the time zone The attached is my homework sample. You can have a look at it and estimate the difficulty level of
IE5002 Homework 2 1/2 1. An article in IEEE International Symposium on Electromagnetic Compatibility (Vol. 2, 2002, pp. 667 –670) describes the quantification of the absorption of electromagnetic energy and the resulting thermal effect from cellular phones. The experimental results were obtained from in vivo experiments conducted on rats. The arterial blood pressure values (mmHg) for the control group (8 rats) during the experiment are th t and for the test group (9 rats) are t h . hht (a) Is there evidence to support the claim that the test group has higher mean blood pressure? Assume that both populations are normally distributed, but the variances are not equal.(b) Calculate aconfidence interval to answer the question in part (a). 2. The diameter of steel rods manufactured on two different extrusion machines is being investigated. Two random samples of sizes n1=15 and n2=17 are selected, and the sample means and sample variances are ens hstQ ee hh respectively. Assume that and that the data are drawn from anormal distribution. hht (a) Is there evidence to support the claim that the two machines produce rods with different mean diameters? (b) Construct a95% CI for the difference in mean rod diameter. Interpret this interval. 3. Fifteen adult males between the ages of 35 and 50 participated in astudy to evaluate the effect of diet and exercise on blood cholesterol levels. The total cholesterol was measured in each subject initially, and then 3months after participating in an aerobic exercise program and switching to alow-fat diet, as shown in the following table. hht (a) Do the data support the claim that low-fat diet and aerobic exercise are of value in IE5002 Homework 2 2/2 producing amean reduction in blood cholesterol levels? (b) Find a95% CI on the mean reduction in blood cholesterol level. 4. In semiconductor manufacturing, wet chemical etching is often used to remove silicon from the backs of wafers prior to metallization. The etch rate is an important characteristic in this process and known to follow anormal distribution. Two different etching solutions have been compared, using two random samples of 10 wafers for etch solution. The observed etch rates are as follows (in mils/min): Test the hypothesis H0: against H1: using hht and draw conclusions.
