Answer:
a. 0.403
Step-by-step explanation:
Confidence interval concepts:
A confidence interval has two bounds, a lower bound and an upper bound.
A confidence interval is symmetric, which means that the point estimate used is the mid point between these two bounds, that is, the mean of the two bounds.
The margin of error is the difference between the two bounds, divided by 2.
Confidence interval of (0.253,0.553)
The bounds are 0.253 and 0.553, so the point estimate is:
[tex]p = \frac{0.253 + 0.553}{2} = 0.403[/tex]
This means that the correct answer is given by option A.