Type+I+and+Type+II+errors

Type I and Type II Errors (Hypothesis Testing) (GWU EMSE-271)
Index | Topics (Logical Lectures) | Lectures | Problems | Readings | References | Concepts [confidence intervals | null hypothesis | acceptance and rejection terminology | Type I and Type II errors | power | p-value]

"There are two kinds of error, classified as "Type I error" and "Type II error," depending upon which hypothesis has incorrectly been identified as the true state of nature.

- EMSE 271, Fall 2009 (Slide 76)


 * "Type I error**, also known as an "**error of the first kind**", an **α error**, or a "**false positive**": the error of rejecting a null hypothesis when it is actually true. Plainly speaking, it occurs when we are observing a difference when in truth there is none. An example of this would be if a test shows that a woman is pregnant when in reality she is not. Type I error can be viewed as the error of excessive credulity.


 * "Type II error**, also known as an "**error of the second kind**", a **β error**, or a "**false negative**": the error of failing to reject a null hypothesis when it is in fact not true. In other words, this is the error of failing to observe a difference when in truth there is one. An example of this would be if a test shows that a woman is not pregnant when in reality she is. Type II error can be viewed as the error of excessive skepticism." - [|Wikipedia]

To compute the Type II error you need to be a little more specific than for a Type I error. " The value of Beta depends on how we define Ho is false ." (Slide 77); in the voltage.xls spreadsheet, have green centered around, versus __ centered around blue. Calculating grey area under the green curve based on the limits established by the blue curve. - Van Dorp. Words don't match the picture. CHECK

Managed to loose some edit heres. Power funciton. Using to check for good sample size. Words from Van Dorp on making mu = 1 in setting up to determine type II error. Hope others have them. CHECK



- EMSE 271, Fall 2009 (Slides 76 and 78)


 * ==> Review the voltage.xls spreadsheet Type I and Type II Errors tab.**


 * Sources:**
 * EMSE 271, Fall 2009 (Slides 74, 76, 77 and 78)
 * Type I and type II errors. (2009, September 7). In //Wikipedia, The Free Encyclopedia//. Retrieved 19:13, September 7, 2009, from []