Cannot run docker run hello-world as non root user

Hi,
I followed the steps at http://docs.docker.com/engine/installation/rhel/ to create the docker group and then added my user to the docker group and did a exit of the xterm and then logged back into it and still when I do “docker run hello-world” as that user, I see this error:
Cannot connect to the Docker daemon. Is the docker daemon running on this host?
I’ve searched on the web too but it all points to the same solution but do not know why its not working. Pls. help

Thanks
Dimple

Use

sudo docker run hello-world