Question Suppose that the recovery period, in days, for patients having back surgery is normally distributed with an unknown mean and standard deviation. The recovery period lengths of 39 randomly sampled back surgery patients are used to estimate the mean of the population. What t-score should be used to find the 99% confidence interval for the population mean? df to.10 to.05 to.025 to.01 to.005 . . . . . 36 1.306 1.688 2.028 2.434 2.719 37 1.305 1.687 2.026 2.431 2.715 38 1.304 1.686 2.024 2.429 2.712 39 1.304 1.685 2.023 2.426 2.708 40 1.303 1.684 2.021 2.423 2.704 Use the portion of the table above or a calculator. If you use a calculator, round your answer to three decimal places. Provide your answer below