Answer:
The point estimate used was of $69,821.
The error bound is of $101.
Step-by-step explanation:
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 error bound is half the difference between these two values.
In this question:
90% confidence that the mean household income in the U.S. falls between $69,720 and $69,922.
Point estimate:
(69720+69922)/2 = 69821
The point estimate used was of $69,821.
Error bound:
(69922 - 69720)/2 = 101
The error bound is of $101.