Please enable JavaScript.
Coggle requires JavaScript to display documents.
Confidence Intervals (Confidence Intervals for the Mean when the…
Confidence Intervals
Confidence Intervals for
the Mean when the Standard Deviation
(σ) of a Population is Known
Assumptions
The sample size is at least 30 (n ≥ 30)
The population standard deviation (σ) is known
Standard Error of the Mean
limit and a lower confidence limit
Margin of Error
Interpreting a Confidence Interval
Changing Confidence Levels
Confidence Intervals for the Mean with Small Samples when σ is Known
With n < 30 the Central Limit Theorem cannot be applied, so we can’t say the sampling distribution will be approximately normal…
but the sampling distribution is always normal (regardless of sample size) if the population is normally distributed
Confidence Intervals for the Mean with Small Samples when σ is Known
Confidence Intervals for
the Mean when the Standard Deviation
(σ) of a Population is Unknown
Sample Standard Deviation
Student’s t-distribution
3 interval endpoints:
2
confidence
1 Standard error of the mean
1
Point Estimates