Seawater is believed to have a mean fluoride concentration of 1.3 mg/L. A marine biologist is concerned that the level of fluoride in a particular area is higher than this and is killing the ocean life. So she plans to collect data and use it to address the following statistical question: Is there evidence that the mean fluoride level here is higher than 1.3 mg/dL? State the null hypothesis and the alternative hypothesis for this question, using appropriate notation and including the appropriate unit.