Step 1 :State the null hypothesis \( H_0: \mu = 98.6^{\circ} \mathrm{F} \) and the alternative hypothesis \( H_a: \mu < 98.6^{\circ} \mathrm{F} \)
Step 2 :Calculate the test statistic using the formula \( t = \frac{\bar{x} - \mu}{s / \sqrt{n}} \) where \( \bar{x} \) is the sample mean, \( \mu \) is the hypothesized mean, \( s \) is the sample standard deviation, and \( n \) is the sample size
Step 3 :Find the P-value associated with the calculated test statistic
Step 4 :Compare the P-value to the significance level \( \alpha = 0.01 \)
Step 5 :If the P-value is less than \( \alpha \), reject the null hypothesis
Step 6 :Since the P-value \( 0.0027 \) is less than the significance level \( \alpha = 0.01 \), we reject the null hypothesis
Step 7 :Conclude that the mean temperature of humans is less than \( 98.6^{\circ} \mathrm{F} \)
Step 8 :The final answer is \( \boxed{\text{Reject } H_0} \)