BUSINESS STATISTICS 5-1 CONFIDENCE INTERVAL
5. Confidence Intervals
Confidence Interval for the Population Mean When
the Population Standard Deviation is Known
Confidence Intervals for When is Unknown - The
t Distribution
Large-Sample Confidence Intervals for the Population
Proportion
The Finite-Population Correction Factor
Confidence Intervals for the Population Variance
Sample Size Determination
One-Sided Confidence Intervals
Summary and Review of Terms
ernational University – School of Business Assoc. Prof. Ho Thanh Phong
, BUSINESS STATISTICS 5-2 CONFIDENCE INTERVAL
5.1 Introduction
• Consider the following statements:
– x = 550
• A single-valued estimate that conveys little information
about the actual value of the population mean.
– We are 99% confident that is in the interval [449,551]
• An interval estimate which locates the population mean
within a narrow interval, with a high level of confidence.
– We are 90% confident that is in the interval [400,700]
• An interval estimate which locates the population mean
within a broader interval, with a lower level of confidence.
ernational University – School of Business Assoc. Prof. Ho Thanh Phong
, BUSINESS STATISTICS 5-3 CONFIDENCE INTERVAL
Types of Estimators
• Point Estimate
– A single-valued estimate.
– A single element chosen from a sampling distribution.
– Conveys little information about the actual value of the population
parameter, about the accuracy of the estimate.
• Confidence Interval or Interval Estimate
– An interval or range of values believed to include the unknown
population parameter.
– Associated with the interval is a measure of the confidence we
have that the interval does indeed contain the parameter of interest.
ernational University – School of Business Assoc. Prof. Ho Thanh Phong
5. Confidence Intervals
Confidence Interval for the Population Mean When
the Population Standard Deviation is Known
Confidence Intervals for When is Unknown - The
t Distribution
Large-Sample Confidence Intervals for the Population
Proportion
The Finite-Population Correction Factor
Confidence Intervals for the Population Variance
Sample Size Determination
One-Sided Confidence Intervals
Summary and Review of Terms
ernational University – School of Business Assoc. Prof. Ho Thanh Phong
, BUSINESS STATISTICS 5-2 CONFIDENCE INTERVAL
5.1 Introduction
• Consider the following statements:
– x = 550
• A single-valued estimate that conveys little information
about the actual value of the population mean.
– We are 99% confident that is in the interval [449,551]
• An interval estimate which locates the population mean
within a narrow interval, with a high level of confidence.
– We are 90% confident that is in the interval [400,700]
• An interval estimate which locates the population mean
within a broader interval, with a lower level of confidence.
ernational University – School of Business Assoc. Prof. Ho Thanh Phong
, BUSINESS STATISTICS 5-3 CONFIDENCE INTERVAL
Types of Estimators
• Point Estimate
– A single-valued estimate.
– A single element chosen from a sampling distribution.
– Conveys little information about the actual value of the population
parameter, about the accuracy of the estimate.
• Confidence Interval or Interval Estimate
– An interval or range of values believed to include the unknown
population parameter.
– Associated with the interval is a measure of the confidence we
have that the interval does indeed contain the parameter of interest.
ernational University – School of Business Assoc. Prof. Ho Thanh Phong
