Li = [499.5 500 501 502 501 499.5 ...
        501.5 500 501.5 501];

Lm = mean(Li)
sigma_L = std (Li)
sigma_Lm = sigma_L / sqrt(10)

Tol = 0.25
uTol = Tol / sqrt(3)

uL  = sqrt (sigma_L^2 + uTol^2)
uLm = sqrt (sigma_Lm^2 + uTol^2)

nu = length(Li) - 1
nu_eff = uL^4 / (sigma_L^4 / (length(Li)-1))  % relation de Welch-Satterthwaite

k = 2.26
UL = k*uL
ULm = k*uLm

disp ('Indication du resultat')
disp (['L_ind = ' num2str(Lm,4) ' +/- ' num2str(UL,2) ' mm' ])
disp (['L_moy = ' num2str(Lm,4) ' +/- ' num2str(ULm,2) ' mm' ])