Kinds of quant data- measured variables, quantified to any resolution desired, e.g. weight, length or temp, called continuous variables
ratio variables= ratios make sense, to compare masses, can use different units and same ratio
Interval variables= ratios do not make sense. can't say 20 degrees is twice 10, comparing intervals makes sense (difference between 20 and 10 is the same as 20 and 30), zero point is arbitrary.
Two variables: measured case= line and scatter plots, if one variable is a response and the other an explanatory, predictor or independent variable, response should be plotted on vertical and other on horizontal. time on x, depth/height on y