Question

An optometrist is interested in the effects of different brands of eyedrops she wants to know if different drops affect the accuracy of a standard vision test. Some researchers think that Brand A may have more adverse effects on an individual’s ability to correctly report the letters in the vision test and Brand B or Brand C. There is also some speculation that the effect of the drops on vision differs dramatically for individuals who are far-sighted compared to those who are near-sighted.

Answer 1

Afandomized comparative approach - Sbatified fondomizalian: DOO As it is given that fur-sighted and near-sighted will bhave different effectis, that variable has to be stratified. that is, the randomization has to be done Seftrolely for lo sighted ond near-sighted subjects. So, we will have three groups for subjects who are randomly assigned to brand A, B ore in far-sighted subjects. and al will have other three group of subjects randomly assigned to A, B ore in near-signted as subjeds. Below diagram explain the randomization process far-sighted Brand A Board c] V V V VVVVVVV OOOOOO Brand B7 Near-sighted Brand B7 Brand A7 Brand c?