In order to secure participants for his study, Jason uses class rosters from instructors. Jason selects every 5th person on the instructor’s class rosters for participation in his experiment. Jason is using sampling.

Systematic sampling.

Explanation:

Systematic sampling is a kind of sampling that has to do with taking samples at regular intervals from a population, the population is given numbers a number is chosen randomly by dividing the population by the sample size(a portion of the large population which is used for the experiment).

Systematic sampling is used to get an unbiased statistics from the the large population.

From the question we can see that "Jason selects every 5th person on the instructor’s class rosters for participation in his experiment" which is done by dividing the population by the sample size.

Jason is using SYSTEMATIC SAMPLING.

Explanation: SYSTEMATIC SAMPLING is defined as a statistical method involving the selection of the subset of a population in which larger population are selected according to a random starting point but with a fixed, periodic interval. Jason selecting every 5th person on the instructor’s class rosters for participation in his experiment is an example of selecting at random with a fixed periodic interval.

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