Statistics Confidence Intervals (1 Viewer)

Users Who Are Viewing This Thread (Users: 0, Guests: 1)

1. Polotical parties rely heavily upon polling to measure their supports in the electorate. Below are the results of a poll conducted in 1996 for four (i only listed the one needed) political parties.
Level Count Probability Stderr Prob
N 250 .211 .0119
Total 1193
4 levels

2. Construct and interpret a 95% confidence interval for the level of support for the N Party in 1996

I only know how to do confidence intervals when a mean ans standard deviation is given using the formula : Mean+- Z*(Sq rt(sx/n)
Last edited:


Homework Helper
The outline for a confidence interval for a proportion is

Point estimate +/- margin of error

You're given the point estimate, the sample size, and standard error. Look in your book to find how to find the margin of error from this information.

The Physics Forums Way

We Value Quality
• Topics based on mainstream science
• Proper English grammar and spelling
We Value Civility
• Positive and compassionate attitudes
• Patience while debating
We Value Productivity
• Disciplined to remain on-topic
• Recognition of own weaknesses
• Solo and co-op problem solving