The effectiveness of a blood-pressure drug is being investigated. An experimenter finds that, on average, the reduction in systolic blood pressure is 56.5 for a sample of size 339 and standard deviation 18.5. Estimate how much the drug will lower a typical patient's systolic blood pressure (using a 80% confidence level). Enter your answer as a tri-linear inequality accurate to one decimal place (because the sample statistics are reported accurate to one decimal place). ___< < ____ Answer should be obtained without any preliminary rounding.