week 3 E text Scott Ward

week 3 E text Scott Ward - o Chapter Exercises 10.30 In...

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

View Full Document Right Arrow Icon
o Chapter Exercises 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? p-hat (red) = 20 / 153248 = 1.304 x 10 ^ -4 p-hat (yellow) = 4 / 135035 = 2.9622 x 10 ^ -5 (a) State the hypotheses. H o : p (red) – p (yellow) = 0 H 1 : p (red) – p (yellow) < 0 (b) State the decision rule and sketch it. CV with a = 1% = 2.326 (c) Find the sample proportions and z test statistic. p-hat (red) = .0001 p-hat (yellow) = .00002 test stat = [(20 / 153,348) - (4 / 135,035)] / sqrt [(0.00002 + (0.0001) x 0.999979 / 135035 )] = 2.961 (d) Make a decision. The test of 2.96 is larger than the CV of 2.36 so must reject the H 0 (e) Find the p-value and interpret it. p-value = .0015. This means the red trucks had a higher evidence of having more
Background image of page 1

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

View Full DocumentRight Arrow Icon
Image of page 2
This is the end of the preview. Sign up to access the rest of the document.

Page1 / 2

week 3 E text Scott Ward - o Chapter Exercises 10.30 In...

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