Table 1.

Features extracted from magnetic data.

Features	Equation
Minimum	$min=min\left(\mathit{magnetisamples}\right)$
Maximum	$max=max\left(\mathit{magnetisamples}\right)$
Mean	$\mu =\frac{1}{n}{\sum }_{i=1}^n{x}_i$
Trimmed mean	${\mu }_{0.25}=\frac{1}{n}{\sum }_{i=1}^n{x}_i$
Median	$\tilde{x}=\frac{x\lceil nx÷2\rceil +x\lceil nx÷2+1\rceil }{2}$
Root mean square	${rms}_x=\sqrt{\frac{1}{n}(x_1^2+x_1^2+\dots +x_n^2)}$
Standard deviation	$\sigma =\sqrt{\frac{1}{n}{\sum }_{i=1}^n{(x_i-\mu )}^2}$
Interquartile	$IQR=\frac{3}{4}{(n+1)}^{th}-\frac{1}{2}{(n+1)}^{th}$
Percentiles (1, 50, 75, 99)	$i=\frac{{np}_i}{100}+0.5$
Mean absolute deviation	$MAD=\frac{{\sum }_{i=1}^n|x_i-\overline{x}|}{n}$
Kurtosis	$k=\left\{\frac{n(n+1)}{(n-1)(n-3)\frac{{\sum }_{i=1}^n{(x_i-\tilde{x})}^4}{{\sigma }^4}}\right\}-\frac{3{(n-1)}^2}{(n-2)(n-3)}$
Coefficient of variance	$\widehat{C_v}=\frac{\sigma }{\tilde{x}}$
Shanon’s entropy	$H\left(X\right)=-{\sum }_{i=0}^{N-1}{p}_i{log}_2{p}_i$
Skewness	${Sk}_p=\frac{\overline{x}-mode}{\sigma }$
Variance	${\sigma }^2=\frac{1}{n}{\sigma }_{i=1}^n{(x_i-\mu )}^2$