474 / 762
474
Chapter 11: Confidence Intervals – Large Samples
proportion of adults who go to bed between 10:00 pm and midnight is
between 0.4580 and 0.6220 (to four decimal places) or between 45.80% and
62.20%.
Figure 11- 5:
Workbook Output with the Confidence
Interval for
Example 11-2
Note:
Observe that the workbook gave a slightly different answer than that
obtained by working the formula directly. This is due to rounding.
Example 11-3
:
In a random sample of 200 persons, 74% of them said that
when they purchase a new vehicle, they do not consult a consumer ratings
publication, such as Consumer Reports. Determine a 95% confidence
interval estimate for the true proportion of people who do not consult a
consumer publication when purchasing a new vehicle.
Click here for the Large Sample Confidence Interval for a Single Population Proportion Workbook