Using the definition of a confidence interval, it is found that the 90% confidence interval for the average cost for healthcare of a senior citizen receiving Medicare is ($12,000, $14,000).
A confidence interval is the <u>sample mean plus/minus the margin of error</u>.
- In this problem, the sample mean is of $13,000.
- The margin of error is of $1,000.
Hence:
$13,000 - $1,000 = $13,000
$13,000 + $1,000 = $14,000
The interval is ($12,000, $14,000).
A similar problem is given at brainly.com/question/24869727
