We investigate the relation between the Doppler factor determined from variations in total flux at 22 and 37 GHz , and the apparent transverse velocity determined from VLBA observations at 2 cm .
The data are consistent with the relativistic beaming theory for compact radio sources , in that the distribution of \beta _ { app } / \delta _ { var } , for 30 quasars , is roughly consistent with a Monte Carlo simulation .
The intrinsic temperature appears to be \sim 2 \times 10 ^ { 10 } K , close to the “ equipartition value ” calculated by Readhead ( 1994 ) .
We deduce the distribution of Lorentz factors for a group of 48 sources ; the values range up to about \gamma = 40 .