Answer:
70
Step-by-step explanation:
it is given that score varies from 500 to 2200
so range =2200-500=1700
standard deviation [tex]s=\frac{range}{4}=\frac{1700}{4}=425[/tex]
Error E=100
Confidence level =95%=0.95
significance level α=1-0.95=0.05
[tex]z_{\frac{\alpha }{2}}=z_{\frac{0.05}{2}}=z_{0.025=1.96}[/tex] from the z table
sample size [tex]n\geq\left ( z_\frac{\alpha }{2}\times \frac{s}{E} \right )^2[/tex]
[tex]n\geq\left ( 1.96\times \frac{425}{100} \right )^2[/tex]
[tex]n\geq69.3889[/tex]
so n will be 70
