Availability of cloud resources to the cloud users is considered as the serious challenge that pose security essentialities during the process of on-demand service provision. Moreover, a specific type of attack named Reduction of Quality (RoQ)-based DDoS attack is determined to be vulnerable in the cloud computing since it exploits the benefits of the embedded adaptive load balancing and admission control methods of the environment. In this paper, an Efficient Adaptive Load Balancing Scheme-based on Wilcoxon–Mann–Whitney Hypothesis Test (EALBS-WMW-HT) is proposed for mitigating Reduction of Quality-based DDoS attack in order to minimize its influence for enhancing the degree of availability to the cloud users. This proposed EALBS-HT scheme uses the merits of statistical testing on the traffic flow and contributes to the detection of RoQ-based DDoS attack such that they does not disturb the inherent load balancing process of the cloud environment. The experiments of the proposed EALBS-HT scheme revealed an excellent detection accuracy, true positive rate and true negative rate with minimized false negative rate studied on par with the baseline approaches considered for analysis.