Chi-Squared confidence intervals - Confidence Intervals
Chi-Squared confidence intervals
Lessons
Notes:
To estimate a population variance a Chi-Squared distribution is used,
• Chi-Squared:
: sample size
: sample standard deviation
: population standard deviation
: is also called "degrees of freedom"
• Chi-Square table gives critical value area to the right
The Confidence interval for the variance is given by:
• < <
-
1.
Determining Degrees of Freedom
How many degrees of freedom does a sample of size, -
2.
Determining the Critical Value for a Chi-Square Distribution and
If a Chi-Squared distribution has 8 degrees of freedom find and , with a
