The effectiveness of a blood-pressure drug is being investigated. An experimenter finds that, on average, the reduction in systolic blood pressure is 35.2 mmHg (millimeters of mercury) for a sample of size 259 and a sample standard deviation 17.1 mmHg. How much of mmHg will lower for a typical patient's systolic blood pressure after taking the drug? Estimate with a 95% confidence. Preliminary: a. Is it safe to assume that n 30 ? O Yes O No Confidence Interval:What is the 95% confidence interval to estimate the population mean? Round your answer to one decimal place.