Page 50 - BA2 Integrated Workbook - Student 2017
P. 50

Chapter 3





                           Correlation





               5.1   Types of correlation

               The reliability of the analysis we have carried out depends on the strength of the
               relationship between the two variables. In our line of best fit and least squares
               regression examples we have assumed a strong linear relationship but this may not
               always be the case. The strength of the relationship between variables is known as
               correlation.

               Two variables are said to be correlated if they are related to one another, or, more
               precisely, if changes in the value of one tend to accompany changes in the other.

                 y                                            y












                                               x                                             x
                        Strong positive                              Strong negative
                y              ion                          y                ion











                        Perfect positive       x                     Perfect negative       x
                               ion                                          ion











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