suppose that we want to investigate whether curfews correlate with differences in grades for students in middle school. we select a random sample of 81 middle school students. the variables are curfew (yes/no) and grade (a letter grade that represents the average grade across courses). is there an association between grade and curfew? or are these two variables independent? we use the data to conduct a chi-square test of independence at the 5% level. in the table, the observed count appears above the expected count in each cell. what can we conclude? a b c d total curfew yes 10 8.667 28 30 15 14 1 1.3333 54 curfew no 3 4.333 17 15 6 7 1 0.6667 27 total 13 45 21 2 81 chi-square test: statistic df value p-value chi-square 3 1.4796703 0.687 group of answer choices there is a statistically significant association between curfew and grades. there is not a statistically significant association between curfew and grades. a curfew helps students to perform better academically. nothing, because the conditions for use of the chi-square test are not met.