3. Normal Distribution: the old voltage meter has a large uncertainty in the reading. The actual voltage of our battery is 3.0 V. The reading from the meter is a random variable with a normal probability distribution around 3.0 V, of which the standard deviation is 0.5 V. (1) Write out the mathematical form of the probability density function as a function of the voltage reading X. (2) Plot this probability density function. (3) Plot the corresponding cumulative probability function (4) Calculate E[X], Var(X), σ(X) (5) Calculate Q0, Q2 and Q4.