Answer:
[tex]H_0:\mu_1-\mu_2=0[/tex]
[tex]H_a: \mu_1-\mu_2<0[/tex]
Step-by-step explanation:
Null hypothesis[tex](H_0)[/tex] is a statement with shows that there is no statistical difference between the group being tested.
Alternative hypothesis[tex](H_a)[/tex] is a statement with shows that there is a statistical difference between the group being tested.
Let [tex]\mu_1[/tex] and [tex]\mu_2[/tex] represent the mean fitness level for female teens and male teens respectively.
Given : Researchers suspected that the fitness level for female teens is lower than for male teens, and wanted to check whether the data would supported this hypothesis.
i.e. he wanted to check if [tex]\mu_1<\mu_2[/tex]
Thus , the appropriate pair of hypotheses in this case would be :-
[tex]H_0:\mu_1=\mu_2[/tex]
[tex]H_a: \mu_1<\mu_2[/tex]
i.e. [tex]H_0:\mu_1-\mu_2=0[/tex]
[tex]H_a: \mu_1-\mu_2<0[/tex]