The problem of volume test, V/Vm, in zero pressure and matter dominated Friedmann universe model is explored under various values of deceleration parameter qo. The following conclusions are drawn. (i) For different values of qo, the change of V/Vm is sensitive at small values of z. Since values of V/Vm are very small at small values of z, this change exerts little effect on the average values of V/Vm. (ii) when values of z and zm are fixed for each member of a sample, large values of qo yield larger values of V/Vm, especially in the case of large z. (iii) For qo<1, the method of volume test is reliable. When qo>2, especially qo>3, this method has to be used with caution at large z.