An experimenter has prepared a drug-dose level that he claims will induce sleep for at least 80% of people suffering from insomia. After examining the dosage, it is believed that his claims regarding the effectiveness of his dosage are inflated. In an attempt to prove or disprove his claim, a prescribed dosage of the drug was administered to a random sample of n = 112 individuals. It was observed that 77 people had a sleep induced due to the drug. The null hypothesis for this study is given by Ho: p = 0.8 versus the alternative hypothesis H_a : p < 0.8. With 95% confidence level, what is the test statistics for this study?

Write the answer with 2 decimal places.