The test is a right-tailed test, where the null hypothesis asserts that less than 10% of treated subjects experience headaches. The critical region is on the right side of the distribution, examining if the observed proportion is significantly greater than 10%. Here option A is correct.
The given problem involves testing a claim about the proportion of treated subjects experiencing headaches, and the null hypothesis is that less than 10% of treated subjects experience headaches. The alternative hypothesis is typically focused on demonstrating that the proportion is significantly different from the claimed value.
In this case, since the null hypothesis is framed as "less than 10%," the test is right-tailed. The critical region for rejection is on the right side of the distribution, indicating that the test is checking if the observed proportion is significantly greater than 10%.
In a right-tailed test, you would compare the test statistic (calculated from the sample data) to the critical value from the right side of the normal distribution to determine whether to reject the null hypothesis. Here option A is correct.
Complete question:
A certain drug is used to treat asthma. In a clinical trial of the drug, 28 of 277 treated subjects experienced headaches (based on data from the manufacturer). The accompanying calculator display shows results from a test of the claim that less than 10 % of treated subjects experienced headaches. Use the normal distribution as an approximation to the binomial distribution and assume a 0.01 significance level to complete parts (a) through (e) below. Is the test two-tailed, left-tailed, or right-tailed?
A - Right tailed test
B - Left-tailed test
C - Two-tailed test