How to find critical value

In a recent poll, 1087 randomly selected adults were asked whether they approve of labor unions; 64% said yes. a. In 1936, about 66% of adults approved of labor unions. At the 5% significance level, do the data provide sufficient evidence to conclude that the percentage of adults who approve of labor unions has decreased since 1936? b. In 1963, roughly 65% of adults approved of labor unions. At the 5% significance level, do the data provide sufficient evidence to conclude that the percentage of adults who approve of labor unions has decreased since 1963? Click here to view page 1 of the table of areas under the standard normal curve. Click here to view page 2 of the table of areas under the standard normal curve. a. What are the hypotheses for the one-proportion z-test? Ho: p= 0.66 ; Ha P