Question 191934: From her firm’s computer telephone log, an executive found that the mean length of 64 telephone calls during July was 4.48 minutes with a standard deviation of 5.87 minutes. She vowed to make an effort to reduce the length of calls. The August phone log showed 48 telephone calls whose mean was 2.396 minutes with a standard deviation of 2.018 minutes.
(a) State the hypotheses for a right-tailed test. (b) Obtain a test statistic and p-value assuming unequal variances. Interpret these results using α = .01. (c) Why might the sample data not follow a normal, bell-shaped curve? If not, how might this affect your conclusions?
Answer by stanbon(75887)   (Show Source):
You can put this solution on YOUR website! From her firm’s computer telephone log, an executive found that the mean length of 64 telephone calls during July was 4.48 minutes with a standard deviation of 5.87 minutes.
Ho: u = 4.48
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She vowed to make an effort to reduce the length of calls.
Ha: u < 4.48
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The August phone log showed 48 telephone calls whose mean was 2.396 minutes with a standard deviation of 2.018 minutes.
(a) State the hypotheses for a right-tailed test.
It should be a left-tailed test since she want to REDUCE the call times.
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(b) Obtain a test statistic and p-value assuming unequal variances. Interpret these results using α = .01.
I ran a T-Test with a TI calculator and got the following results:
t = -7.1548
p-value = 0.00000000238
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(c) Why might the sample data not follow a normal, bell-shaped curve? If not, how might this affect your conclusions?
I'.ll leave that discussion to you.
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Cheers,
Stan H.
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