“…When choosing blocks of length n = 2 , the estimator ̂ 2 Mean results in a differencebased estimator which considers ⌊N∕2⌋ consecutive non-overlapping differences: Difference-based estimators have been considered in many papers, see Von Neumann et al (1941), Rice (1984), Gasser et al (1986), Hall et al (1990), Dette et al (1998), Munk et al (2005), Tong et al (2013), among many others. Dai and Tong (2014) discussed estimation approaches based on differences in nonparametric regression context, Wang et al (2017) considered an estimation technique which involves differences of second order, while Tecuapetla-Gómez and Munk (2017) proposed a difference-based estimator for m-dependent data. An ordinary differencebased estimator of first order, which considers all N − 1 consecutive differences, is [see, e.g., Von Neumann et al (1941)]:…”