The recommended daily dietary allowance for zinc among males older than age 50 years is 15 mg/day. A study reports the following summary data on intake for a sample of 12 males age 65-74 years: xbar=11.3. Assuming that the true distribution for zinc intake is normally distributed with variance 6.43, does the data indicate that the average daily zinc intake in the population of all males 65-74 falls below the recommended allowance?

Consider testing the hypotheses H0:=15 versus H1:<15 at level of significance =0.05.

Below what value does xbar need to be for us to reject H0 in favor of H1? Give your answer to two decimal places.