Well, both are correct, though sometimes referred to by different names: Sleep (aka Hibernation) and Suspend (aka Standby) are both two separate Power Saving states.
Here is a mini writeup (meant for another thread) for your amusement:
With Hibernation (Sleep), your work is saved to a hibernation file and the computer switches off: If set correctly in BIOS, it can be woken (read: switched on) again by moving the mouse, or touching a keyboard button.
With Standby (Suspend), your work is saved to memory. Leaving the Standby (Suspend) state is faster than leaving the Hibernation (Sleep) state. If Standby (Suspend) is in effect for an extended period, then the computer state switches to Hibernation (Sleep) mode.
These modes can be regulated usually by changing the duration of each state in whatever Power Settings are available in your OS.