Answer
The null hypothesis can not be rejected and this means that it can not be
concluded that the average farm in Oregon differs from the national mean.
Work Step by Step
Given that, $\mu=444, \sigma=52, n=40, \bar x =430$, then,
$H_{0}:\mu=444.\\ H_{1}:\mu \ne 444.$
$Z=\frac{\bar x- \mu}{\frac{\sigma}{\sqrt{n}}}=\frac{430- 444}{\frac{52}{\sqrt{40}}}\approx -1.70$
$P-value =2\times(1-P(Z\leq 1.70)=2\times(1-0.9554)=0.0892$
Since $\alpha=0.05$ and $P-value =0.0892$, the null hypothesis can not be rejected.
