Answer
The distribution must be normal.
$μ_{x̄} = 64$
$σ_{x̄} = 4.907$
Work Step by Step
In order to use the normal model to compute probabilities involving the sample mean, the distribution must be normal. The sampling distribution of x̄ is given as:
$μ_{x̄} = μ = 64$
$σ_{x̄} = σ/\sqrt n = 17/\sqrt 12 = 4.907$
