Question 1: The average time it takes a group of adults to complete a certain achievement test is 46.2 minutes.  The standard deviation is 8 minutes.  Assume the variable is normally distributed. a) Find the probability that a randomly selected adult will complete the test in less than 43 minutes. b) Find the probability that if 50 randomly selected adults take the test, the mean time it takes the group to complete the test is less than 43 minutes. c) Does it seem reasonable that an adult would finish the test in less than 43 minutes?  Explain. d) Does it seem reasonable that the mean of the 50 adults could be less than 43 minutes?  Explain.

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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Question 1: The average time it takes a group of adults to complete a certain achievement test is 46.2 minutes.  The standard deviation is 8 minutes.  Assume the variable is normally distributed.

a) Find the probability that a randomly selected adult will complete the test in less than 43 minutes.
b) Find the probability that if 50 randomly selected adults take the test, the mean time it takes the group to complete the test is less than 43 minutes.
c) Does it seem reasonable that an adult would finish the test in less than 43 minutes?  Explain.
d) Does it seem reasonable that the mean of the 50 adults could be less than 43 minutes?  Explain.

 

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