Consider again the uniform distribution on the interval [a,b]. Since the probability is 0 that one of the endpoints a orb will be chosen, it is irrelevant whether the distribution is regarded as a uniform distribution on a given interval is constant over that interval, and the constant value of the p.d.f. is the reciprocal of the length of interval. It is not possible to define a uniform distribution over the interval x≥a because the length of this interval is infinite.