Answer: 90% confidence interval would be (0.448, 0.552).
Step-by-step explanation:
Since we have given that
x = 125
n = 250
So, [tex]\hat{p}=\dfrac{x}{n}=\dfrac{125}{250}=0.5[/tex]
We need to find the 90% confidence interval.
so, z = 1.64
So, interval would be
[tex]\hat{p}\pm z\sqrt{\dfrac{\hat{p}(1-\hat{p})}{n}}\\\\=0.5\pm 1.64\sqrt{\dfrac{0.5\times 0.5}{250}}\\\\=0.5\pm 0.0519\\\\=(0.5-0.0519,0.5+0.0519)\\\\=(0.448,0.552)[/tex]
Hence, 90% confidence interval would be (0.448, 0.552)