The amount of time taken by a bank teller to serve randomly arriving customers has a normal distribution with a mean of 2.5 minutes and a standard deviation of 30 seconds. (a) For two of the customers, what is the probability that both are served in 2 minute or less? (b) If four customers are served, what is the probability that at least one of them have serving time that exceeds 3 minutes?

The amount of time taken by a bank teller to serve randomly arriving customers has a normal distribution with a mean of 2.5 minutes and a standard deviation of 30 seconds. (a) For two of the customers, what is the probability that both are served in 2 minute or less? (b) If four customers are served, what is the probability that at least one of them have serving time that exceeds 3 minutes?

A First Course in Probability (10th Edition)

10th Edition

ISBN:9780134753119

Author:Sheldon Ross

Publisher:Sheldon Ross

Chapter1: Combinatorial Analysis

Section: Chapter Questions

Problem 1.1P: a. How many different 7-place license plates are possible if the first 2 places are for letters and...

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For a standardized psychology examination intended for psychology majors, the historical data show that scores have a mean of 515 and a standard deviation of 175. The grading process of this year's exam has just begun. The average score of the 40 exams graded so far is 518. What is the probability that a sample of 40 exams will have a mean score of 518 or more if the exam scores follow the same distribution as in the past? Carry your intermediate computations to at least four decimal places. Round your answer to at least three decimal places. Sub Continue
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