Answer:
z statistic equals 1.5
Step-by-step explanation:
z-score can be calculated using the formula
[tex]z=\frac{p(s)-p}\sqrt{\frac{p(1-p)}{N}}[/tex] where
putting these numbers in the formula we get:
[tex]z=\frac{0.1225-0.1}\sqrt{\frac{0.1*0.9}{400}}[/tex] = 1.5