Week 5 Team Paper Regression Analysis

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Chapter 10 and Chapter 11 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? (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. (Pages 397-399) a) State the Hypothesis: (Pages 347-348) a. H0: There is no significant difference in the accident rate of red fire trucks compared to yellow fire trucks. b. H1: There is a significant difference in the accident rate of red fire trucks compared to yellow fire trucks. b) State the decision rule and sketch it: (Pages 350-353) You must reject the null hypothesis if the test statistic of the calculated value is less than the critical value of z. [pic] c) Find the sample proportions and z test statistic: (Pages 351; 357-359) |Hypothesis test for two independent proportions | | | | | | | | | |p1 |p2 |pc | | | |0.0001 |0.00003 |8.33878E-05 | p (as decimal) | | |0.0001 |0.00003 |8.33878E-05 | p (as fraction) | | |19.997 |4.05105
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