That really depends on the country. Some yogurts are very much dead where as in Switzerland they must be alive . Same thing with so many other items.
You get yogurt by using bacteria to process milk. In order to do their processing, the bacteria need to be alive. So, for example, adding living yogurt to milk will get you more yogurt, but adding dead yogurt to milk will get you milk with some dead yogurt in it.
Whether or not refrigerated yoghurt-ish products are live or not is another question. If you live in a jurisdiction which restricts the term "yoghurt" to products containing live cultures, you can rely on whether or not the refrigerated product uses the term in its description. Otherwise I have no idea.