Q9. A study was conducted to examine for open-angle glaucoma and unilateral hemifield defects sample of 16 subjects. They have the sample data for the ages (years) of the subjects. If the stud test whether or not the mean age of the population from which the sample may be presumed to drawn is less than 60 years, what type of the hypothesis testing it would be? A. one sided /-test B. one sided z-test C. strictly one sided 1- D. none of test