Division 3.2.1 Calculation of the slope of the regression line for each gear

The linear regression line is calculated using the anchor point and the four correlated additional measurements.

${\mathrm{Slope}}_k=\frac{\sum _{j=1}^5\left(n_j-\bar{n}\right)\left(L_i-\bar{L}\right)}{\sum _{j=1}^5{\left(n_j-\bar{n}\right)}^2}$(in dB/1 000 min^-1)

With$\bar{L}=\frac{1}{5}\sum _{j=1}^5{L}_j$and$\bar{n}=\bar{n}\frac{1}{5}\sum _{j=1}^5{n}_j$

where n_j = engine speed measured at line BB'