Step 1 :The null hypothesis (H0) is a statement of no effect or no difference. In this case, it would be that the mean body temperature of a healthy adult is 98.6 degrees Fahrenheit.
Step 2 :The alternative hypothesis (H1) is what you might believe to be true or hope to prove true. In this case, it would be that the mean body temperature of a healthy adult is not 98.6 degrees Fahrenheit.
Step 3 :As for the type of test, since we are not specifying whether we believe the mean body temperature to be higher or lower than 98.6 degrees Fahrenheit, we should conduct a two-tailed test.
Step 4 :Final Answer: \[ \begin{array}{l} H_{0}: \text{The mean body temperature of a healthy adult is } 98.6^{\circ} \mathrm{F} \\ H_{1}: \text{The mean body temperature of a healthy adult is not } 98.6^{\circ} \mathrm{F} \end{array} \] The type of hypothesis test to be conducted is a two-tailed test.