*the `samhda` (**usingr**) data set contains information on marijuana usage among children as collected at the substance abuse and mental health data archive. the variable `marijuana` indicates whether the individual has ever tried marijuana. a 1 means yes, a 2 no. if it used to be that 50% of the target population had tried marijuana, does this data indicate an increase in marijuana usage? do a significance test of proportions to decide\.\*