Chapter 21B - Understanding Confidence Intervals The...

Info iconThis preview shows pages 1–9. Sign up to view the full content.

View Full Document Right Arrow Icon
Understanding Confidence Intervals The General Form
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Outline Understanding Confidence Intervals Confidence Intervals for a Mean Different Level Confidence Intervals
Background image of page 2
Definitions The point estimate of a population parameter is the single value of the sample statistic used to estimate the parameter The 95% Margin of Error (95% M.O.E.) is the value that is added and subtracted to the point estimate to get an interval estimate for the population parameter
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Population Proportion Confidence Interval Point estimator Standard Deviation of Point Estimator 95% Margin of Error n p p p ) ˆ 1 ( ˆ 2 ˆ - ±
Background image of page 4
Estimating Any Population Parameter To estimate any population parameter with a sample statistic, we can still use the 2 standard deviation rule to get the 95% Margin of Error. But the 2 standard deviation rule only applies to the Normally distributed variables. Are all sample statistics (point estimators) Normally distributed?
Background image of page 5

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Examples of Normally Distributed Sample Statistics (Well Quasi) 1000 different samples of size 30 were taken. Get the value of the sample statistic for each sample of 30. Make a histogram of all results. Do all of the sample statistics look Normally Distributed? Frequency 172.5 170.0 167.5 165.0 162.5 160.0 157.5 80 60 40 20 0 224 216 208 200 192 184 176 120 90 60 30 0 96 88 80 72 64 56 48 40 80 60 40 20 0 176 172 168 164 160 156 152 120 90 60 30 0 Mean Maximum Range Median Different Statistics Computed On Samples of Size 30
Background image of page 6
Central Limit Theorem Nearly any statistic computed on a sample is normally distributed if the sample size is large enough.
Background image of page 7

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Result To estimate a population parameter with 95% confidence point estimate ± 95% Margin of Error
Background image of page 8
Image of page 9
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 06/15/2011 for the course STAT 110 taught by Professor Johnson during the Fall '07 term at South Carolina.

Page1 / 24

Chapter 21B - Understanding Confidence Intervals The...

This preview shows document pages 1 - 9. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online