Another approach when N nk ≠ is the use of fractional interval reported by Murthy (1967) [2]. This approach called for taking k Nn = as k without rounding it off to the nearest integer, i.e., the
i unit is selected in the sample if 1 i r jk i −< + ≤ for any ( ) 0,1, 2, , 1 jn= − .