I have 3 sets of data, which I need to graph on a scatter plot and then work with further by comparing them in terms of correlation and so on. Each of the sets of data varies from the other in that the first set has around 100 sets of data values (eg obesity rate of a country and birth rate for a select group of countries), the second has 50 sets of values (obesity rate and birth rate for a different set of countries) and the third only 14 (obesity/birth rate for one last set of countries).
My question is, what sort of sample size should I be using? Should I plot all of the available data for each of the values, or take a sample size of 14, so that the sample size is equal? Also, should I be graphing them all on the one graph or separately?
Thanks for your advice.
My question is, what sort of sample size should I be using? Should I plot all of the available data for each of the values, or take a sample size of 14, so that the sample size is equal? Also, should I be graphing them all on the one graph or separately?
Thanks for your advice.
