Xr12-136 A national health-care system was an issue in the 2008 presidential election campaign and is likely to be a subject of debate for many years.

The issue arose because of the large number of Americans who have no health insurance. Under the current system, free health care is available to poor people, whereas relatively well-off Americans buy their own health insurance. Those who are considered working poor and who are in the lower-middleclass economic stratum appear to be most unlikely to have adequate medical insurance. To investigate this problem, a statistician surveyed 250 families whose gross incomes last year were between $10,000 and

$25,000. Family heads were asked whether they have medical insurance coverage (2  Has medical insurance, 1  Doesn’t have medical insurance). The statistics practitioner wanted an estimate of the fraction of all families whose incomes are in the range of

$10,000 to $25,000 who have medical insurance.

Perform the necessary calculations to produce an interval estimate with 90% confidence.