The sketches below represent scatter diagrams for the way in which variables x, y and z change over time, t, in a given chemical experiment. They are labelled , and . (a) State which of the diagrams indicate that the pair of variables (i) is not correlated; (ii) shows strong linear correlation. (b) A student is given a piece of paper with five numbers written on it. She is told that three of these numbers are the product moment correlation coefficients for the three pairs of variables shown above. The five numbers are 0.9, 0.04, 1.60 –0.85, –0.20, (i) For each sketch above state which of these five numbers is the most appropriate value for the correlation coefficient. (ii) For the two remaining numbers, state why you reject them for this experiment.
The sketches below represent scatter diagrams for the way in which variables x, y and z change over time, t, in a given chemical experiment. They are labelled , and . (a) State which of the diagrams indicate that the pair of variables (i) is not correlated; (ii) shows strong linear correlation. (b) A student is given a piece of paper with five numbers written on it. She is told that three of these numbers are the product moment correlation coefficients for the three pairs of variables shown above. The five numbers are 0.9, –0.85, –0.20, 0.04, 1.60 (i) For each sketch above state which of these five numbers is the most appropriate value for the correlation coefficient. (ii) For the two remaining numbers, state why you reject them for this experiment.