Bob wanted to conduct research that will delve into knowing the strength of the relationship between post-traumatic stress disorder and the academic performance of nursing students during the final year of nursing school. The type of research design most suited towards his study would be: causal comparitive

Correlational study

Explanation:

Bob's research is geared towards finding the strength of the relationship that exists between post-traumatic stress disorder and the academic performance of nursing students in their finals. The best research design for this is therefore correlational research design since this type of research design is useful when one is interested in finding out the existence of a relationship between 2 variables of interest.

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