Z-test for accident rates
Not what you're looking for?
In Dallas some fire trucks were painted yellow. During the test period, the fleet of red fire trucks made 153,348 runs and had 20 accidents. the fleet of yellow trucks made 135,035 runs and had 4 accidents. At a=.01, did the yellow fire trucks have a significantly lower accident rate?
Zc=2.326
Z=2.961
p-value=.0015
normality not justified
State null and alternative hypothesis.
Select a level of significance.
Identify the test statistics (give formula).
Formulate a decision rule.
Make a decision (compute sample proportions and Z statistic).
Compute p-value and interpret it.
Is the normality assumption fulfilled? Explain.
Purchase this Solution
Solution Summary
Z-test for accident rates of a yellow fire truck is determined. A hypothesis test is used.
Solution Preview
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 ...
Purchase this Solution
Free BrainMass Quizzes
Terms and Definitions for Statistics
This quiz covers basic terms and definitions of statistics.
Measures of Central Tendency
Tests knowledge of the three main measures of central tendency, including some simple calculation questions.
Know Your Statistical Concepts
Each question is a choice-summary multiple choice question that presents you with a statistical concept and then 4 numbered statements. You must decide which (if any) of the numbered statements is/are true as they relate to the statistical concept.
Measures of Central Tendency
This quiz evaluates the students understanding of the measures of central tendency seen in statistics. This quiz is specifically designed to incorporate the measures of central tendency as they relate to psychological research.