The present study is mainly focused to address the uncertainty underlying compressive strength of non-conventional bricks along with clay brick using agro and industrial wastes such as sugarcane bagasse ash and waste marble dust; but utilization of both the materials in a single brick is very scanty. Keeping view on this, an attempt was made in the study to understand the effects of sugarcane bagasse ash along with the waste marble dust as the partially replaced material for the production of bricks. However, the compressive strength of brick is the main critical parameter further an extensive study was also done through the probability study. To undertake the current proposal economically; a semi - automatic fly ash brick manufacturing machine was fabricated locally with hydraulically operating system. To prepare the nonconventional brick, three different types of combinations as Type I, II and III were considered and based on the minimum values of the suggested Indian codal provision for compressive strength, with the composition of fly ash brick as fly ash-25 \%, sugarcane bagasse ash (SBA)-20 \%, sand-30 \%, cement-5\%, waste marble dust-20 \% and for clay bricks as clay of 65 \% with SBA 35 \% are finalized for further statistical analysis. The study concluded that, the variability of the characteristics compressive strength of both fly ash and clay brick can be described with normal distribution at 5\% significance level. The regression analysis for the compressive strength of bricks concluded with a linear relationship with R-2 = 0.996 and 0.992 respectively for both the bricks type considered. Further the embedded irregularities in the data of above-mentioned bricks types confirm the adoption of statistical techniques. Owing to the satisfactory results of characteristic compressive strength, the utilization of sustainable fly ash bricks in the present study can be encouraged subjected to the ample availability of raw materials in a locality. (C) 2021 The Authors. Published by Elsevier Ltd.