According to the Merck Veterinary Manual, the average resting heart rate for a certain type of sheep dog is 115 beats per minute (bpm). A Montana farmer notices his aging sheep dog has been acting more lethargic than usual and wonders if her heart rate is slowing. He measures her heart rate on 15 occasions and finds a sample mean heart rate of 118.2 bpm.

Which of the following hypotheses should the farmer test?

A. [tex]H_0: \mu \geq 118.2, \, H_a: \mu < 118.2[/tex]
B. [tex]H_0: \mu \geq 115, \, H_a: \mu < 115[/tex]
C. [tex]H_0: \mu = 115, \, H_a: \mu \neq 115[/tex]
D. [tex]H_0: \bar{x} = 118.2, \, H_a: \bar{x} \neq 118.2[/tex]
E. [tex]H_0: \mu < 115, \, H_a: \mu > 115[/tex]
F. [tex]H_0: \bar{x} \geq 115, \, H_a: \bar{x} > 115[/tex]