The relative frequency tables display data collected from 230 students. 

1. 	participates in after school activity	no after school activity	total
   arrives home within 2 hours of school dismissal	3%	40%	43%
   arrives home 2 or more hours after school dismissal	42%	15%	57%
   total	45%	55%	100%

   1. What percentage of students participate in after school activities? How many students participate in after school activities?
   2. What percentage of students arrive home 2 or more hours after dismissal? How many students arrive home 2 or more hours after school dismissal?

2. 	aspiring professional athlete	aspiring STEM career	total
   prefer physical education	77%	23%	100%
   prefer math	18%	82%	100%

   1. What percentage of students who prefer math aspire to have a career in STEM?
   2. What percentage of students who prefer physical education aspire to have a career in STEM?
   3. Is there evidence of an association between students’ career aspirations and subject preference? Explain your reasoning.

3. 	9th grade	12th grade
   curfew	95%	90%
   no curfew	5%	10%
   total	100%	100%

   1. Of the students in 12th grade, what percentage have a curfew?
   2. Of the students in 9th grade, what percentage have a curfew?
   3. Is there evidence of an association between students’ grade level and whether they have a curfew? Explain your reasoning.

1. Invent a pair of variables that you think will have an association. Explain your reasoning.
2. Invent a pair of variables that you think will not have an association. Explain your reasoning.