A group of medical researchers is interested in determining the effect of the drug Gravalux on a person's reaction time. To do this, the researchers select at random 15 patients who were prescribed Gravalux. Before taking Gravalux, the patients were asked to press a button as soon as a blue dot appeared on a screen. The times (in seconds) it took for the patients to press the button were recorded. Then, the patients were given Gravalux. After an hour, they were asked to repeat the blue dot experiment and their new reaction times were recorded. The data and the differences (After minus Before) are shown in the table below. Patient 6 8 10 11 12 13 14 15 After 0.210 0.195 0.237 0.211 0.125 0.225 0.430 0.201 0.412 0.272 0.435 0.424 0.405 0.366 0.276 Before 0.161 0.161 0.313 0.227 0.347 0.198 0.196 0.162 0.372 0.291 0.341 0.192 0.221 0.324 0.394 Difference (After - Before) 0.049 0.034 -0.076 -0.016 -0.222 0.027 0.234 0.039 0.040 -0.019 0.094 0.232 0.184 0.042 -0.118 Send data to calculator Assume that the population of these differences in reaction times (After minus Before) is approximately normally distributed. Construct a 99% confidence interval for J , the population mean difference in reaction times before and after taking Gravalux. Then find the lower and upper limits of the 99% confidence interval. Carry your intermediate computations to four or more decimal places. Round your answers to three or more decimal places. (If necessary, consult a list of formulas.) Lower limit: X Upper limit