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AFAIK, $n$ qubits together can be described by using a column vector (also called State vector) of $2^n$ complex amplitudes such that sum of the squares of mod of all these complex amplitudes will be $1$.
However, as per below snippet for qsphere visualisation, what does the spikes of different colours denote?
from qiskit.quantum_info import random_statevector
from qiskit.visualization import plot_state_qsphere
num_qb = 3
my_sv = random_statevector(2**num_qb)
plot_state_qsphere(my_sv)
The size of the points on the spike shows the probability of the state and the color represents the phase of the state , for example state $|000\rangle$ is blue so it has a phase of 0 and the point is larger that the rest of them so it has the highest probability. state $|110\rangle$ is the second largest to it, so it has the second largest probability, and it is green so its phase is in pi to 3*pi/2 range. you can check here and here for more information about qsphere
