Normal distributions: Probabilities and percentiles
Not what you're looking for?
The highway police in a certain state are using aerial surveillance to control speeding on a highway with a posted speed limit of 55 miles per hour. Police officers watch cars from helicopters above a straight segment of this highway that has large marks painted on the pavement at 1-mile intervals. After the police officers observe how long a car takes to cover the mile, a computer estimates that cars speed. Assume that the errors of these estimates are normally distributed with a mean of 0 and a standard deviation of 3.41 miles per hour.
a. The state police chief has directed his officers not to issue a speeding citation unless the aerial units estimate of speed is at least 66 miles per hour. What is the probability that a car travelling at 58 miles per hour or slower will be cited for speeding?
b. Suppose the chief does not want his officers to cite a car for speeding unless they are 99% sure that it is travelling at 58 miles per hour or faster. What is the minimum estimate of speed at which a car should be cited for speeding?
Purchase this Solution
Solution Summary
This solution shows how to calculate probabilities and find percentiles of a normal distribution
Purchase this Solution
Free BrainMass Quizzes
Measures of Central Tendency
Tests knowledge of the three main measures of central tendency, including some simple calculation questions.
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.
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.
Terms and Definitions for Statistics
This quiz covers basic terms and definitions of statistics.