This is not to say that it is impossible to do so, but it will either be impractical or unethical to do so. For example, a researcher may be interested in the effect of illegal, recreational drug use (the independent variable(s)) on certain types of behaviour (the dependent variable(s)).
This tutorial was last updated on March 17, 2015 and is only intended for desktop/laptop users running the Mac OS X 10.10.x (or above) operating system. While Apple's Safari is a well-known favorite among Mac users, OS X's default browser is far from the only game in town. With popular alternatives such as Chrome and Firefox available on the platform, along with other formidable options like Maxthon and Opera, it not uncommon to have several browsers installed on the same system.
Most people stick with the browser that came with their computers. Internet Explorer is a well-known browser because it comes with virtually every PC. Safari is well known to Mac users (Apple computers) because that's the primary browser on those computers. It's admirable to be loyal, but feel free to take this new information and explore your browser choices.