Answer:
The statistic for this case would be:
![z=\frac{\hat p -p_o}{\sqrt{(\hat p(1-\hat p))/(n)}}](https://img.qammunity.org/2021/formulas/mathematics/college/vjxg0egio1tj0f381izc9k32xq0ab67khu.png)
And replacing we got:
![z= \frac{0.436-0.4}{\sqrt{(0.436*(1-0.436))/(700)}}= 1.92](https://img.qammunity.org/2021/formulas/mathematics/college/qyvhflkddoz1b6v935h8r0cr6y7uywqzyi.png)
Explanation:
For this case we have the following info:
represent the sample size
represent the number of employees that earn more than 50000
![\hat p=(305)/(700)= 0.436](https://img.qammunity.org/2021/formulas/mathematics/college/4ctz6v13w91x6t1f03dp1l0c7nrvhtaxrp.png)
We want to test the following hypothesis:
Nul hyp.
![p \leq 0.4](https://img.qammunity.org/2021/formulas/mathematics/college/fk1e3vb8cchl8ep7bms3m812wj645bip7p.png)
Alternative hyp :
![p>0.4](https://img.qammunity.org/2021/formulas/mathematics/college/5sud3wdywbiilc3ekhgr5goa9rf6yd72z0.png)
The statistic for this case would be:
![z=\frac{\hat p -p_o}{\sqrt{(\hat p(1-\hat p))/(n)}}](https://img.qammunity.org/2021/formulas/mathematics/college/vjxg0egio1tj0f381izc9k32xq0ab67khu.png)
And replacing we got:
![z= \frac{0.436-0.4}{\sqrt{(0.436*(1-0.436))/(700)}}= 1.92](https://img.qammunity.org/2021/formulas/mathematics/college/qyvhflkddoz1b6v935h8r0cr6y7uywqzyi.png)
And the p value would be given by:
![p_v = P(z>1.922)= 0.0274](https://img.qammunity.org/2021/formulas/mathematics/college/gw8k10bo0otuyalyqzz4a0hh8ohbkucgpu.png)