Professor boredom has noticed that his students keep falling asleep during his lectures. he thinks that keeping the lights in the lecture hall on at their brightest level will to keep students awake. he decides to give the same lecture to three groups of people. he holds one class session with bright lights, one class session with normal lighting, and one class session with dim lights. professor boredom has a teaching assistant count the number of sleepers at the end of each dependent variable(s) in the above experiment is (are)

The answer is "the number of sleeping students" is dependent variable.

A dependent variable is the variable being tried and estimated in a scientific investigation as in the given case it is the students while an independent variable is the variable that is changed or controlled in the experiment to test the impacts on the dependent variable which in the given case are the number of students.

for many centuries there were important factors which the economies of the muslim empires developed increasingly. they applied economic procedures in production, investment, finance, taxation and property. they used to tax certain goods (for example: harvest), they charged interest on money lent, they signed contracts with merchants; they relied on a common currency, and they used checks as well as promissory notes. with the money collected by means of taxation, the government provided the needy with an income. in addition, trading networks covered huge distances, so far regions started to have contact and exchange goods. this trade network covered areas of asia, africa and europe.