Answer:
The value of the standardized z-test statistic is -6.4.
Explanation:
The test statistic is:
![z = (X - \mu)/(s)](https://img.qammunity.org/2022/formulas/mathematics/college/9vaue0z1d7rtqau4af5xlobjbvfs1z0zeu.png)
In which X is the sample mean,
is the value tested at the null hypothesis, and s is the standard error.
0.28 is tested at the null hypothesis:
This means that
![\mu = 0.28](https://img.qammunity.org/2022/formulas/mathematics/college/8017ig708jxaeqxp1z8l3g2ga7na189jzq.png)
p ^ 0.216 with SE 0.01
This means that
![X = 0.216, s = 0.01](https://img.qammunity.org/2022/formulas/mathematics/college/nesgyspu0w6txzahua918hy6qt7dad9yn6.png)
Then
![z = (X - \mu)/(s)](https://img.qammunity.org/2022/formulas/mathematics/college/9vaue0z1d7rtqau4af5xlobjbvfs1z0zeu.png)
![z = (0.216 - 0.28)/(0.01)](https://img.qammunity.org/2022/formulas/mathematics/college/sj5pylzbeelfx683slvnkgx1g5556muarp.png)
![z = -6.4](https://img.qammunity.org/2022/formulas/mathematics/college/ibf52f1vb375m9bataigfykj6r11f6nxvy.png)
The value of the standardized z-test statistic is -6.4.