Remember that home inspection you arranged before purchasing your home? The inspector tested electrical outlets and talked about correcting problems. You purchased the home but not have gotten around to correcting the outlet problems.
You can perform some basic testing with a simple outlet tester as pictured here. Most have three indicator lamps that tell you whether the outlet is wired correctly. Just plug the tester into the outlet and check the color-coded lights. Now, the testers are not perfect and may give a false reading from time to time, but they can give you a good overall indication of the outlet and circuit wiring.
Note that you can't use the testers in two-prong outlet. These inexpensive testers are available at all hardware and big box stores. You should also consider buying a more sophisticated tester that includes a test button for ground fault circuit (GFCI) protected circuits. When you push the button, the tester will evaluate whether the GFCI will trip when current is leaking. Found a wiring problem? Then it's time to hire an electrician who will accurately diagnose the specific problem and correct it.