Athree letter word used to show division in a word problem

Researchers were interested in whether relaxation training decreases the number of headaches a person experiences. they randomly assigned 20 participants to a control group or a relaxation training group and noted the change in number of headaches each group reported from the week before training to the week after training. which statistical analysis should be performed to answer the researchers' question?

Classify the following number. −9.070707…

Convert the density of surface sea water to metric tons/cubic meter