An Empirical Study of Second Order Rotatable Designs under Tri-Diagonal Correlated Structure of Errors Using a Pair of Partially Balanced Incomplete Block Type Designs
Keywords:
Rotatability, correlated errors, incomplete block designsAbstract
In this paper, following the works of Das (1997, 1999 and 2003), Rajyalakshmi and Victorbabu (2014, 2016 and 2018), second order rotatable designs under tri-diagonal correlated structure of errors using a pair of partially balanced incomplete block type designs (PBIBD) is suggested. Here we study the variance function of estimated response for different values of tri-diagonal correlated coefficient () and distance from the center (
d) for various factors. This method gives designs with less number of design points than the corresponding second order rotatable designs (SORD) under tri-diagonal correlated structure of errors using pairwise balanced designs (PBD) and balanced incomplete block type designs (BIBD).