Table 2 .Standard deviation The covariation of two casual variable is equal to correlation between them , multiplied on product of their standard deviations ?ij designates factor of correlation (correlation coefficient ) between profitableness on the securities i and profitableness on the securities j . Factor of correlation normalize covariation for simplification of comparison with other pairs casual variable . Factor of correlation always lays in an interval between -1 and 1 . If it is equal -1 , it means complete negative correlation , if 1...











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