You$$d like to investigate the causal relationship between online classes and students$$ performance, to see if online classes improve or worsen learning experience. You collected data of all ECON $382$ students at the Queens college for the last four semester. You have $1200$ students in your dataset. In your dataset, you know the grade of each student and if the class was online or in person. So$,$ you regress grade on the binary variable which is one for online and zero for in person classes. The coefficient for your independent variable $($online class$)$ is positive and significantly different from zero $($at $1\%$ level of significance$).$ So$,$ based on these results, can you say that online classes caused better grades?