A corporation randomly selects 150 salespeople and finds that 66% who have never taken a self-improvement course would like such a course. The firm did a similar study 10 years ago in which 60% of a random sample of 160 salespeople wanted a self-improvement course. The groups are assumed to be independent random samples. Let π₁ and π₂ represent the true proportion of workers who would like to attend a self-improvement course in the recent study and the past study, respectively. Referring to Scenario, what is/are the critical value(s) when testing whether the current population proportion is higher than before if α = 0.05?
A. ± 1.645
B. + 1.96
C. ± 1.96
D. + 1.645