Mechanical Properties of Malaysian Timbers: The Weighted Mean and Combined Standard Deviation Values

The mechanical properties of Malaysian timbers are formally reported based on botanical species in the values of arithmetic mean, standard deviation and number of tested specimen. There appears a need to represent the mechanical properties of timbers which take into account the variability among the multiple species of a timber of a trade name. An accurate description of the mechanical properties of timber will ultimately increases the level of engineering safety, optimises the utilisation of material and assists on the budgetary decision. This article demonstrates the mathematical formulae to calculate the weighted mean and combined standard deviation values for more precise representation of the mechanical properties of timber.