The effectiveness of a blood-pressure drug is being investigated. An experimenter finds that, on average, the reduction in systolic blood pressure is 19.7 for a sample of size 21 and a standard deviation of 20.7. Estimate how much the drug will lower a typical patient's systolic blood pressure (using a 99% confidence level).Assume the data is from a normally distributed population.

Enter your answer as a tri-linear inequality accurate to three decimal places.

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