In the past, the average length of an outgoing telephone call from a business office has been 144 seconds. A manager wishes to check whether that average has decreased after the introduction of policy changes. A sample of 100 telephone calls produced a mean of 141 seconds, with a standard deviation of 26 seconds. Perform the relevant test at the 0.05 level of significance. 1) In the past, te average length of an outgoing telephone call trom a business oflice hanbeen 143 seconds. A manager wishes to check whether that average has decreased after theintroduction of poliky changes. A sample of 100 telephone calls produced a mean of 140 seconds,with a standard deviation of 25 seconds. Perform the relevant test at the 0.05 level of significance.2) In the past, the avernge length of an outgoing telephone call from a business office hasbeen 144 secoads. A manager wishes to check whether that vernge has decreased after theintroduction of policy changes. A sample of 100 telephone calls produced a mean of 141 secondi,with a standard deviation of 26 seconds. Perfonm the relevaat test at the 0.05 level of significance.3) In the past, the average length of an outgoing lelephone call from a business office hasbeen 145 seconds. A manager wishes to check wbether that average has decreased after theintroduction of policy clanges. A saple of 100 lelephone calls produced a mean of 142 seconds,with a standard deviation of 27 secondi. Perform the relevat test at the 0.05 level of significance.

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From the given information, let X be the length of an outgoing telephone call. n = 100, x-bar = 141…

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In the past, the average length of an outgoing telephone call from a business office has been 144 seconds. A manager wishes to check whether that average has decreased after the introduction of policy changes. A sample of 100 telephone calls produced a mean of 141 seconds, with a standard deviation of 26 seconds. Perform the relevant test at the 0.05 level of significance.

In the past, the average length of an outgoing telephone call from a business office has been 144 seconds. A manager wishes to check whether that average has decreased after the introduction of policy changes. A sample of 100 telephone calls produced a mean of 141 seconds, with a standard deviation of 26 seconds. Perform the relevant test at the 0.05 level of significance.

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) In the past, te average length of an outgoing telephone call trom a business oflice han
been 143 seconds. A manager wishes to check whether that average has decreased after the
introduction of poliky changes. A sample of 100 telephone calls produced a mean of 140 seconds,
with a standard deviation of 25 seconds. Perform the relevant test at the 0.05 level of significance.
2) In the past, the avernge length of an outgoing telephone call from a business office has
been 144 secoads. A manager wishes to check whether that vernge has decreased after the
introduction of policy changes. A sample of 100 telephone calls produced a mean of 141 secondi,
with a standard deviation of 26 seconds. Perfonm the relevaat test at the 0.05 level of significance.
3) In the past, the average length of an outgoing lelephone call from a business office has
been 145 seconds. A manager wishes to check wbether that average has decreased after the
introduction of policy clanges. A saple of 100 lelephone calls produced a mean of 142 seconds,
with a standard deviation of 27 secondi. Perform the relevat test at the 0.05 level of significance.

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