Problem 3. Confidence interval for mean change from pre to post intervention Researchers investigated the possible beneficial effects of singing on well-being during a single singing lesson. One of the variables of interest was the change in cortisol as a result of the singing lesson. Subject | Before After Diff 1 214 232 18 2 362 276 86 3 202 224 22 4 158 412 254 5 403 562 159 6 219 203 -16 307 340 33 8 331 313 -18 Determine the 95% two-sided C.I. for MD (difference in mean cortisol levels from pre to post). Problem 4. APC Resistance Activated protein-C (APC) resistance is a serum marker that has been associated with thrombosis (the formation of blood clots often leading to heart attacks) among adults. APC values for 5 randomly chosen individuals at high-risk for heart attack are listed below. 2.2, 3.4, 2.7, 3.3, 3.0 Note: The sample standard deviation is s = 0.49 Calculate a 95% confidence interval for the mean APC level of individuals from this population