A study was carried out to evaluate the safety of motorcycle helmets. Forty randomly selected helmets were subjected to a certain impact test and 20 were found to show no damage. The researcher concluded with some confidence that the proportion of all helmets that would show no damage when subjected to such an impact was smaller than 62.5% (i.e. 5/8). With what confidence was this conclusion made? A [ ] 0.83 B [ ] 0.91 C [ ] 0.93 D [X] 0.95
Added by Mar R.
Close
Step 1
We are given that 40 helmets were randomly selected and subjected to an impact test. Show more…
Show all steps
Your feedback will help us improve your experience
Ivan Kochetkov and 70 other Intro Stats / AP Statistics educators are ready to help you.
Ask a new question
Labs
Want to see this concept in action?
Explore this concept interactively to see how it behaves as you change inputs.
Key Concepts
Recommended Videos
The National Occupant Protection Use Survey (NOPUS) was conducted to provide probability-based data on motorcycle helmet use in the United States. The survey was conducted by sending observers to randomly selected roadway sites where they collected data on motorcycle helmet use, including the number of motorcyclists wearing a Department of Transportation (DOT)-compliant helmet (National Highway Traffic Safety Administration website, January 7,2010 ). Sample data consistent with the most recent NOPUS are shown below: $$ \begin{array}{lcc} \text { Region } & \text { DOT-Compliant } & \text { Noncompliant } \\ \text { Northeast } & 96 & 62 \\ \text { Midwest } & 86 & 43 \\ \text { South } & 92 & 49 \\ \text { West } & 76 & 16 \\ \text { Total } & \frac{76}{350} & \frac{16}{170} \end{array} $$ a. Use the sample data to compute an estimate of the probability that a motorcyclist wears a DOT-compliant helmet. b. The probability that a motorcyclist wore a DOT-compliant helmet five years ago was .48 , and last year this probability was .63. Would the National Highway Traffic Safety Administration be pleased with the most recent survey results shown above? c. What is the probability of DOT-compliant helmet use by region of the country? What region has the highest probability of DOT-compliant helmet use?
Donald A.
Recommended Textbooks
Elementary Statistics a Step by Step Approach
The Practice of Statistics for AP
Introductory Statistics
Transcript
18,000,000+
Students on Numerade
Trusted by students at 8,000+ universities
Watch the video solution with this free unlock.
EMAIL
PASSWORD