Astudy investigated the job satisfaction of teachers allowed to choose supplementary curriculum for their classes versus teachers who were assigned all curricular resources for use in their classes. the authors of the study wanted to know if the two groups of teachers had different levels of job satisfaction. they will use a significance level of 5% for their test. upper-tail values a 5% 2.5% 1% critical z-values 1.65 1.96 2.58 what is (are) the critical value(s) for z in this study?