Chapter 12: Estimation

What is estimation?

Sample estimation calculation: Single sample t

• A researcher would like to determine the average reading ability for third grade students in the school.   
• A sample of n = 25 students is selected and each student takes a standardized reading achievement test. 
• The average score for the sample is M (sample mean) =72 with SS (variance) = 2400. 
• Use the sample results to construct a 99% confidence interval for the population mean. 

**With 99% confidence, we estimate that the population mean is between 66.408 and 77.594.

 

Formulas for estimation

An Overview of Estimation

Estimation

Definition

The inferential process of using sample statistics to estimate population parameters is called estimation.

Precision And Confidence In Estimation

Definition

For a point estimate, you use a single number as your estimate of an unknown quantity.

For an interval estimate, you use a range of values as your estimate of an unknown quantity.

When an interval estimate is accompanied by a specific level of confidence (or probability), it is called a confidence interval.