Answer:
Z = -6.3
Step-by-step explanation:
Given that:
[tex]\mathbf{H_o :p= 0.28}[/tex]
[tex]\mathbf{H_o :p < 0.28}[/tex]
Since the alternative hypothesis is less than 0.28, then this is a left-tailed hypothesis.
Sample sixe n = 800
[tex]\hat p[/tex] = 0.217
The standard error [tex]S.E(p) = \sqrt{\dfrac{p(1-p)}{n}}[/tex]
[tex]S.E(p) = \sqrt{\dfrac{0.28(1-0.28)}{800}}[/tex]
[tex]S.E(p) \simeq0.015[/tex]
Since this is a single proportional test, the test statistics can be computed as:
[tex]Z = \dfrac{\hat p - p}{\sqrt{\dfrac{p(1-p)}{n}}}[/tex]
[tex]Z = \dfrac{0.217- 0.28}{0.01}[/tex]
Z = -6.3
