It has been my experience that one clutch holds all the same sex. I suppose if the temperature is in the median area it would be possible, but that's not my experience.
All things considered I think it would average out to 50/50. If you knew the species and incubation temps, it might sway those guesstimated odds a bit.
I incubate on the high side of the temperature range and I still get a few males along with the mostly females. There have been mixed sexes in every group of clutchmates I've bought.