# Statistics Confidence Intervals (1 Viewer)

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

#### sjooff111

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