L28Type2Errors

L28Type2Errors - MGT 2250 — Lesson 28 » Determining the...

Info iconThis preview shows pages 1–5. Sign up to view the full content.

View Full Document Right Arrow Icon
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Background image of page 2
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Background image of page 4
Background image of page 5
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: MGT 2250 — Lesson 28 » Determining the Probability of Type II Errors April 11, 2011 Definition: Type II errors are made when the mill hypothesis is NOT rejected when it should have been (i.e. that the null hypothesis is actually false and therefore the alternative hypothesis is true). The symbo for the probability of making a Type 11 error is the Greek letter beta ). _ While the beta is dependent on the alpha (and the “n” and the true population mean), it is NOT equal to one minus the alpha! The procedure for determining beta follows with an example. Example: A quality control (QC) manager must decide whether to accept a shipment of batteries from a supplier or return it due to unacceptable quality. The quality requirements for these batteries ' demand that they have a useful life of at least 120 hours. To test the quality of the shipment, a sample of Sig batteries will be selected at random and tested. If the sample indicates a mean useful life of this shipment is significantly less tha ours, the shipment will be rejected. (Note: The population standard deviation (sigma) is known to be ghours.) 1.) Develop and state the Nuli Hypothesis and the Alternative ch‘fth'tt.,‘ s YPO esns or 18 es Hgo ‘ [L2 [91] H’dfi [‘7 410/0 2.) Based on the hypotheses, determine the type of hypothesis test: One-tail Upper (l-T-U), One-tail Lower (l-T-L) or Two Tail (2-T) ' [KT-2L, 3.) Specify (set) the level of Significance (alpha —VR) and determine the rejection point - z,p. d2.0‘< Etfuo‘r‘fléfi/{p L28TypeZErrors (H4, Hm “4 U 4.) Determining the beta if the true population mean is 115 hours. WW ‘* M f «if (/1 &\ /A6Tfi39§{)cz ,_ r, Pfl/flfl A Pow%a;7;flr%fi/M A} WPKJJ I flaw/Z: ’ 7? 5.) Determining the beta if the true population mean is 112 hours. 2'2 gf/(a/7/FHZZ [£2 //—/,flr/96?/? ,50’7/ flvflj/_,Doax 7,770? L2 8Type2Errors ‘ I _ 3 _ 6.) Determining the beta if the true population mean is 118 hours. a [IL/H 7.) Determining the “power” of the test. The porer curve. L28TypeZErrors 8.) Example #2: A marketing research firm basis its charges to clients on the assumption that the average phone call lasts 15 minutes. A sample of 35 calls was done to test the assumption that the null hypothesis of the mean being less than or equal to 15 minutes was true. In other words, were the calls actually averaging more than 15 minutes in length? The sample had a standard deviation of 4 minutes. At alpha=0.05, what is the probability of making a Type 11 error if the mean is actually 17 minutes? What is the power of the test? H’s ’{ « a v Cd; '\ [if ,5 a .x I “' ,m f are w” 9 /’ J t v. L28Type2Errors ...
View Full Document

Page1 / 5

L28Type2Errors - MGT 2250 — Lesson 28 » Determining the...

This preview shows document pages 1 - 5. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online