Answer:
0.22
Step-by-step explanation:
Sample given is 500, so use z-score for the critical value
Given 95% confidence interval;
∝=100-95 =5% =0.05
∝/2 = 0.05/2 =0.025 ----because you are interested with one tail area
1-0.025= 0.975 -----area to the left
proceed to z-table to read 0.975 = 1.96 as the critical value
standard deviation from the question is 2.5 but because this is a sample then;
standard error for the mean is= standard deviation/√sample= 2.5/√500
=0.1118
Margin of error=1.96*0.1118 =0.2191
