Answer:
[tex]0.4035+/-0.0845[/tex]
Step-by-step explanation:
The fundamental step would be to determine the values of p and E which i believe is the margin of error in this case. Consider the following two equations;
[tex]p-E=0.319\\p+E=0.488[/tex]
We simply add the two equations and solve for p;
[tex]2p=0.807\\p=0.4035[/tex]
We then substitute this value of p in either equation and solve for E;
[tex]0.4035-E=0.319\\E=0.0845[/tex]
Since we have both p and E, the confidence interval can thus be written as;
[tex]0.4035+/-0.0845[/tex]