A researcher is exploring the effects of physical activity on the onset of puberty in girls. The age of menarche is determined for six young athletes who started serious training before the age of eight. For comparison, the same measure is taken on six girls who started an equally serious and time-consuming regimen, training to play the violin at eight. An additional six girls not involved in any training are included as a control group' [Hint: Begin with degrees of freedom] Answer the following questions and Complete the Source Table below. (10 pts) a . Identify the independent and the dependent variables (2 pts.) Independent variable: Dependent variable a. State the hypotheses in words' (2 pts.) Null hypothesis: Alternative hypothesis: Source SS df MS F 8.26