Week 3 E-Text assignment

Week 3 E-Text assignment - Week 3 E-Text Assignment 10.30...

Info iconThis preview shows pages 1–2. Sign up to view the full content.

View Full Document Right Arrow Icon

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

View Full DocumentRight Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: Week 3 E-Text Assignment 10.30 In Dallas, some fire trucks were painted yellow (instead of red) to heighten their visibility. During a test period, the fleet of red fire trucks made 153,348 runs and had 20 accidents, while the fleet of yellow fire trucks made 135,035 runs and had 4 accidents. At α = . 01, did the yellow fire trucks have a significantly lower accident rate? (a) State the hypotheses. (b) State the decision rule and sketch it. (c) Find the sample proportions and z test statistic. (d) Make a decision. (e) Find the p-value and interpret it. (f ) If statistically significant, do you think the difference is large enough to be important? If so, to whom, and why? (g) Is the normality assumption fulfilled? Explain. a) : : 2 1 2 1 ≠- =- p p H p p H A p1 = red trucks, p2 = yellow trucks b) Reject the null hypothesis if z > 2.3263 2.3263 > shaded area c) 961 . 2 035 , 135 1 348 , 153 1 ) 10 322 . 8 1 ( 10 322 . 8 035 , 135 4 348 , 153 20 1 1 ) 1 ( 10 322 . 8 035 , 135 348 , 153 4 20 5 5 2 1 2 1 5 2 1 2 1 = +-- = +-- = × = + + = + + =--- x x n n p p p p z n n x x p excel stats = Hypothesis test for two independent proportions p1 p2 p c 0.00013 2.96E-05 8.32E-05 p (as decimal)...
View Full Document

This note was uploaded on 12/19/2010 for the course MKT 421 taught by Professor Unknown during the Spring '08 term at University of Phoenix.

Page1 / 5

Week 3 E-Text assignment - Week 3 E-Text Assignment 10.30...

This preview shows document pages 1 - 2. Sign up to view the full document.

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