The effectiveness of a blood pressure drug is being investigated. An experimenter finds that, on average, the reduction in systolic blood pressure is 58.2 for a sample of size 20 and standard deviation 14.2.
Estimate how much the drug will lower a typical patient's systolic blood pressure (using a 80% confidence
level). Assume the data is from a normally distributed population,
Enter your answer as a tri-linear inequality accurate to three decimal places.