1 / 4

# Confidence Intervals for Means - PowerPoint PPT Presentation

Confidence Intervals for Means. point estimate – using a single value (or point) to approximate a population parameter. the sample mean is the best point estimate of the population mean  The problem is, with just one point, how do we know how good that estimate is?

I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.

## PowerPoint Slideshow about ' Confidence Intervals for Means' - alexis-frye

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.

- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript

### Confidence Intervals for Means

• point estimate – using a single value (or point) to approximate a population parameter.

• the sample mean is the best point estimate of the population mean 

• The problem is, with just one point, how do we know how good that estimate is?

• A confidence interval (or interval estimate) is a range of interval of values that is likely to contain the true value of the population parameter.

• confidence interval = estimate  margin of error

• common choices are:

• 90% ( = 0.10);

• 95% ( = 0.05);

• 99% ( = 0.01).

Create a 95% confidence interval for the starting salaries of 20 college graduates who have taken a statistics course if the mean salary is \$43,704, and the standard deviation is \$9879.

• margin of error

s = standard deviation = \$9879

n = sample size = 20

df= degrees of freedom = n-1=19

tcrit=2.093