N	Number of observations (or number of pairs for hypothesis tests)
$t_{\mathrm{mean}}$	Mean thickness of the beam in the direction of loading
$w_{\mathrm{mean}}$	Mean width of the beam
$l_{\mathrm{test}}$	Testing length
$ACS$	Cross-sectional area
V	Volume
$I_{\mathrm{mid}}$	Moment of inertia in mid-span
${\rho }_{\mathrm{app}}$	Apparent density
E	Elastic modulus
f	Strength
$\epsilon$	Strain
U	Strain energy density
con	Index for conventional determination of strain
opt	Index for optical determination of strain
y	Index for yield point (0.2% plastic strain)
u	Index for ultimate point
b	Index for fracture point