UASTAT141Ch21 - β = P(H is not rejected | H is false The...

Info iconThis preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
Ch. 21 - Errors in Hypothesis Testing In any hypothesis test, there is 1 of 2 choices: reject or not reject. There is also 1 of 2 choices as the test applies to reality: H 0 is true or H 0 is false. Actual situation H 0 is true H 0 is false Do not reject H 0 Correct Decision Type II or β error Decision Reject H 0 Type I or α error Correct Decision Def’n: A Type I error occurs when a true null hypothesis is rejected. The value of α represents the prob. of committing this type of error; that is, α = P (H 0 is rejected | H 0 is true) The value of α represents the significance level of the test. A Type II error occurs when a false null hypothesis is not rejected. The value of β represents the prob. of committing a Type II error; that is,
Background image of page 1
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: β = P (H is not rejected | H is false) The value of 1 – β is called the power of the test . It represents the probability of NOT making a Type II error. Example where H : “innocent until proven guilty” Actual situation Innocent Guilty Find not guilty Correct Decision Type II or β error Jury’s decision Find guilty Type I or α error Correct Decision These 2 errors are dependent. For a fixed sample size, lowering α will raise β and vice versa. Decreasing α and β simultaneously requires increasing the sample size. Further information on the errors are not covered in this course....
View Full Document

  • Winter '10
  • PaulCartledge
  • Null hypothesis, Statistical hypothesis testing, Type I and type II errors, Statistical power, β, α

{[ snackBarMessage ]}

Ask a homework question - tutors are online