Statistical significance: hypothesis testing regarding one mean

In the context of hypothesis testing regarding one mean, the test (Z or t) may be statistically significant at the 5% level, but not significant in a practical sense at all. Illustrate the meaning of this statement by citing 3 examples from any area of interest.

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...erimental group than to the control group over the 12 weeks of the experiment?

Market research had shown that travel agencies were primarily concerned with the speed with which reservations can be made. Therefore, the question was whether color displays allow travel agents to book reservations faster. Market research had also shown that in order to justify the higher price of color displays, they must be faster by an average of at least 10 seconds per transaction. Fifty subjects were tested with color displays and 50 subjects were tested with black and white displays. Subjects were slightly faster at making reservations on a color display (M = 504.7 seconds) than on a black and white display (M = 508.2) seconds. Although the difference is small, it was statistically significant at the .05. Clearly, the difference is not big enough to justify the more expensive color displays. Even the upper limit of the 95% confidence interval (seven seconds) is below the minimum needed to justify the cost (10 seconds). Therefore, the experimenter could feel confident in his or her recommendation that the black and white displays should be used. The fact that ...