#13 In One Sample Proportion test, it is important to convert the sample proportion to a z-score first. In this example, we selected a random sample of size 110 from a pool of university students and asked whether they use Facebook on a regular base. Seventy replied yes. Assuming that the population proportion under the null hypothesis is 50%, what is the z-score for the sample proportion?

#4 To investigate the prevalence rate of Hypertension among US adults, we drew a random sample of 70 adults from the US and among them 10 people had hypertension. Please construct a 95% confidence interval for the population proportion of hypertension. Which one of the following results is the closest to your answer? (Hint: use 1.96 as the critical z-value).