An herbal supplements company claims their sleep aid supplement is successful at putting 74% of its users to sleep within a half hour of taking the supplement. Believing the claim overstated the effectiveness of the supplement, a group of doctors decided to conduct their own study to test the company's claim. They collected a random sample of 85 patients with sleeping problems and gave them the supplement. Only 49 of the patients reported they were able to fall asleep within a half hour. What is the test statistic for this one-sample z-test for proportions?