Skewed frequency response of RLC circuit
I believe your results don't match your calculations because of the output impedance of your signal generator. That output impedance is in parallel with your 10k ohms resistor. You didn't specify what generator you are using but chances are its output impedance is either 50 ohms or 600 ohms, both of which are much less than 10k ohms. A parallel RLC circuit should be driven with a high impedance source so as not to load the circuit.  Essentially you should drive it with a current source, not a voltage source.  You can approximate this by putting a large resistor in series with your signal generator, probably at least 100k ohms. Do this and repeat your measurements.