Suppose we are interested in calculating a 95% confidence interval for the mean of a normally distributed population. We've drawn a sample of 10 observations from this population, and found a sample mean of 311.8 and a sample standard deviation of 37.0.

What is the appropriate lower endpoint of the 95% interval for mu? (e.g. If the interval is (3.712,9.674), give 3.712 as your response.)

(Give your response to at least 3 decimal places. Give only your numeric response, and no extra characters or symbols.)