Question

Find the margin of error if the confidence (significant) level is 95%.

1. n = 100, x = 80, s= 2.5

2. n=250, x = 100, s= 3.25

3. n= 300, x = 250, s = 4.15

Answer 1

$E=\frac{z\sigma}{\sqrt{n}}$

1.$E=1.96\times2.5/\sqrt{100}=0.49$

2. $E=1.96\times3.25/\sqrt{250}=0.40$

3. $E=1.96\times4.15/\sqrt{300}=0.47$