Can mindful yoga have a beneficial impact on alcohol use in high-risk adolescents? Read excerpts from the research published in The Journal of Child and Family Studies and answer the questions that follow. (Fishbein et al., “Behavioral and psychophysiological effects of a yoga intervention on high-risk adolescents: A randomized control trial,” Journal of Child and Family Studies, vol. 25 [February 2016]: 518–529, https://doi.org/10.1007/s10826-015-0231-6) Abstract: We designed a 20-session mindful yoga intervention for adolescents attending a school for students at high risk of dropping out. The 69 participants were randomly assigned to control and intervention groups. Survey data were collected before and after the yoga curriculum. At the post test, students in the yoga condition exhibited trends toward decreased alcohol use as compared to control students. 

a. Identify the treatment variable and the response variable.

b. Was this a controlled experiment or an observational study?

c. Based on this study, can you conclude that yoga caused a decrease in alcohol use? Why or why not?