What is the difference in meaning between a dot and an empty circle on a number line graph?

a filled in circle/dot means "greater than or eaqual to/less than or equal to" (depending on which way the arrow is pointing. an empty cirlce means only "greater than/less than". the greater than/less than symbol with the line under it will indicate the filled in circle. the normal greater than/less than symbol willl indicate the hollow cirlce