Six measurements were made of the mineral content (in percent) of spinach, with the following results. It is reasonable to assume that the population is approximately normal. 19.1, 20.1, 20.8, 20.7 , 20.5, 19.3 Find the lower bound of the 95% confidence interval for the true mineral content. Round to three decimal places (for example: 20.015). Write only a number as your answer. Do not write any units.