The objective of this study was to develop a model to predict the viscoelastic material functions of a vinyl ester polymer (Derakane 441-400) with variations in the material properties. Time and temperature dependent statistical distribution parameters were used to obtain the upper and lower limits of the time dependent creep compliances. Short-term tensile creep experiments were conducted at three temperatures below the glass transition temperature. In-plane longitudinal and transverse strain-time histories were measured simultaneously using a digital image correlation technique. Creep compliances were obtained using the generalized viscoelastic constitutive equation with a Prony series representation. This effort involved an analytical study based on experimental results for representing the data scatter in polymer composites.