nickel       copper    aluminium
nickel     1.0000000 -0.114838413  0.101273327
copper    -0.1148384  1.000000000 -0.003052345
aluminium  0.1012733 -0.003052345  1.000000000

Chart 1

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mean median std_dev IQR skewness kurtosis
copper.size 0.8830 0.6823 0.7849 0.9217 1.7713 7.8654
aluminium.size 0.8072 0.5510 0.8986 1.0136 1.8899 8.4006
nickel.dir 0.0447 1.0000 0.9959 2.0000 -0.0895 1.0150
copper.dir 0.0540 1.0000 0.9931 2.0000 -0.1081 1.0235 
[1] 1.282969