A researcher is conducting research on using technology in teaching. The researcher has two groups. The first group receives instruction via a PowerPoint presentation that is online. The second group attends a class and receives instruction from a teacher face to face. The researcher classifies the students based on when they volunteer for the study. The first 50 students who volunteer receive online instruction. The next 50 receive instruction by attending a class with a teacher. The type of instruction the student receives is the:

Standardized variable

Explanation:

Standardized variable: In research methods, the term "standardized variable" is also referred to as "standard score" or "z-score" and is described as one of the different variables that have been "re-scaled" to possess a standard deviation of 1 and a mean of 0. Moreover, these variables tend to contain different students score on a specific test related to the wisdom of social studies, mathematics, and science. However, teachers and authors generally use a standardized variable in contrast with control variables and it is supposed to be "constant" in specific research or an experiment.

In the question above, the given statement represents the "standardized variable".

hope this helps!!:)

answer; i believe the correct answer is prefrontal cortex;

question - in 1827, john walker, a druggist in a small english town, tipped a splint with sulphur, chlorate of potash, and sulphid of antimony, and rubbed it on sandpaper, and it burst into flame. the druggist had discovered the first friction-chemical match, the kind we use to-day. it is called friction-chemical because it is made by mixing certain chemicals together and rubbing them. although walker's match did not require the bottle of acid, nevertheless it was not a good one. it could be lighted only by hard rubbing, and it sputtered and threw fire in all directions. in a few years, however, phosphorus was substituted on the tip for antimony, and the change worked wonders. the match could now be lighted with very little rubbing, and it was no longer necessary to have sandpaper upon which to rub it. it would ignite when rubbed on any dry surface, and there was no longer any sputtering. this was the phosphorus match, the match with which we are so familiar. according the paragraph what was the benefit of the new phosphorus match? it burst into flame when rubbed on sandpaper. it was made by mixing chemicals. it could be ignited on any dry surface. it threw fire in all directions.

answer - matches required natural chemicals