What is the difference between descriptive research and correlational research?

Descriptive research usually involves that the data collected are described by parameters like their central tendency (mode, median, mean) and their dispersion (range, interquartile range, standard deviation). Once there is more than one variable to describe one can go a step further in the research process and calculate the relationship between them. Usually it is expressed in terms of a Pearson correlation, which means that a relationship is expressed in terms of numbers ranging between - 1 and +1, the latter is called a positive relationship, the former means that the relationship is negative (like the bigger an Apple, the less it costs). Zero (0) would indicate no relationship between variables (e.g. no relationship between price and size). It is rare for a correlation to be as strong as 1, most correlations range between .30 and .60. - CPeter