Let us consider a strip-wise habitat of line-segment, like a corridor, to simplify the subject mathematically, and assume that the length of the habitat is 6 and there are n individuals. Here, we assume that the spatial pattern of the individuals is random if the n distances from the left end of the habitat to each individual follow a uniform distribution on the strip. Under such an assumption, the variance of the distances between any two neighbors is represented by the formula nO2(n+ 1)-2(n+2)-1; and the variance between n + 1 distances between n individuals from the left end to the right end to the strip, is represented by the formula O2(n + 1)-X(n + 2)-1. These two kinds of variances can be used for determining (1) the spatial pattern of a population on the strip and (2) the spatial structure within the population, by comparison with the variances calculated from the data. Two examples cited from the literature, a cattle population on a pasture and an aphid population on a sycamore leaf, are presented.KEYWOl~S: distance measure, spatial pattern index, strip-wise habitat of line-segment.