Ascientist in new york and a scientist in california both conducted independent investigations that produced similar results. what does this mean about the data that was collected?

Hypothesis is both testable and falsifiable. To test the hypothesis scientific experiments are conducted, the data analyzed and conclusion reached. When independent labs all over the world perform the experiment and obtain the same results it means that the hypothesis is true and the scientific theory is valid. This means that a scientific consensus was reached.

altitude, density, pressure

air gets less dense the higher the altitude and also the air pressure is less as altitude rises.