Asurvey was conducted on 218 undergraduates from duke university who took an introductory statistics course in spring 2012. among many other questions, this survey asked them about their gpa and the number of hours they spent studying per week. the scatterplot below displays the relationship between these two variables.

a) the explanatory variable is ? study hours/weeks gpa the 218 undergraduates duke university the introductory statistics course and the response variable is ? study hours/weeks gpa the 218 undergraduates duke university the introductory statistics course ?
b) the relationship between the variables is ? strong weak ? positive negative neither positive nor negative and ? linear non-linear .
c) is this experiment or an observational study?
a. observational study
b. experiment
d) can we conclude that studying longer hours leads to higher gpas?

a. yes, we can conclude that studying longer hours leads to higher gpa since this study this is an observational study.
b. no. we cannot conclude that studying longer hours leads to higher gpa since this study is observational.
c. yes, we can conclude that studying longer hours leads to higher gpa since this study is an experiment.
d. no. we cannot conclude that studying longer hours leads to higher gpa since this study is an experiment.
e. we cannot draw any conclusion because the scatterplot has no distinct form.