Answer: The test statistic is -3.322.
Step-by-step explanation:
Since we have given that
n = 431
[tex]\hat{p}=0.42[/tex]
Hypothesis would be :
[tex]H_0:p=0.5\\\\H_1:p\neq 0.5[/tex]
So, the test statistic would be
[tex]z=\dfrac{\hat{p}-p}{\sqrt{\dfrac{p(1-p)}{n}}}\\\\z=\dfrac{0.42-0.5}{\sqrt{\dfrac{0.5\times 0.5}{431}}}\\\\z=\dfrac{-0.08}{0.02408}\\\\z=-3.322[/tex]
Hence, the test statistic is -3.322.