Division 4.3 Calculate the statistical error in the CO2 savings

The statistical error in the CO₂ savings is to be determined in two steps. In the first step the error value of the power is to be determined as a standard deviation being equivalent to a confidence interval of 68 %.

This is to be done by formula (4).

Formula (4):

Where:

${\sigma }_{\bar{x}}$

Standard deviation of arithmetic mean [W];

x_i

Measurement value [W];

$\bar{x}$

Arithmetic mean [W];

n

Number of measurements, which is 5.

In order to calculate the error in the CO₂ savings for a petrol and diesel -fuelled vehicles, the propagation law, expressed in formula (5), is to be applied.

Formula (5):

Where:

$\stackrel{–}{{\mathrm{\Delta C}}_{{\mathrm{CO}}_2}}$

Mean total error of the CO₂ saving [gCO₂/km]

Sensitivity of calculated CO₂ saving related to the type of lighting P_j

σ_Pj

Error of the type of lighting P_j [W]

m

a number of types of lightings in the innovative technology package

Substituting formula (2) in formula (5) results in formula (6) for calculating the error in CO₂ savings for petrol fuelled vehicles.

Formula (6):

Substituting formula (3) in formula (5) results in formula (7) for calculating the error in CO₂ savings for diesel fuelled vehicles.

Formula (7):