Suppose independent observations, ( x₁, ..., xₙ ) are taken from a normal distribution with mean ( θ ) and variance ( θ² ), ( θ ne 0 ). Find the maximum likelihood estimator (MLE) of ( θ ).
a) ( ∑ᵢ=1ⁿ xᵢ/n )
b) ( ∑ᵢ=1ⁿ xᵢ/√n )
c) ( √∑ᵢ=1ⁿ xᵢ²/n )
d) ( ∑ᵢ=1ⁿ xᵢ²/n )
