We study the doping and temperature dependence of the single-particle coher
ent weight, z(A), for high-T-c superconductors Bi2Sr2CaCu2O8+x using angle-
resolved photoemission. We find that at low temperatures the coherent weigh
t z(A) at (pi ,0) is proportional to the carrier concentration x and that t
he temperature dependence of z(A) is similar to that of the c-axis superflu
id density. We show that, for a wide range of carrier concentration, the su
perconducting transition temperature scales with the product of the low-tem
perature coherent weight and the maximum superconducting gap.