More on confidence intervals and margins of error.

1. Required: A High Level of Confidence
and a Small Margin of Error
The Formation 1 by flickr user satosphere

2. Some Senior 4 students in a large high school want to change a
tradition at graduation. Instead of wearing the usual cap and gown, they
want to wear formal clothes. A quick survey of 96 randomly selected
students shows that 41 prefer formal wear.
• How certain can we be that the results would be approximately the
same if another survey of 250 students were done?
• Is it possible that a majority of students prefer formal wear?
• Based on the results of this survey, what are the smallest and
largest numbers of students that would likely be in favour of dressing
formally?
These questions can be answered by constructing a 95% confidence
interval and the margin of error.