Answer:
[tex]\sf z = -16.35[/tex]
formula:
[tex]\sf z = \dfrac{s-p}{\sqrt{\dfrac{p(1-p)}{n} } }[/tex]
Here s = 0.3, p = 0.5, n = 1671
solve:
[tex]\rightarrow \sf z = \dfrac{0.30-0.5}{\sqrt{\dfrac{0.5(1-0.5)}{1671} } }[/tex]
[tex]\rightarrow \sf z = \dfrac{-0.2}{\sqrt{\dfrac{0.25}{1671} } }[/tex]
[tex]\rightarrow \sf z = -16.35[/tex]