29.5 -values: Mean differences
A -value determines if the sample data are consistent with the assumption (Table 28.1), Since , the one-tailed -value is between 2.5% and 16% based on the 68–95–99.7 rule. This is a wide, and inconclusive, interval. Software gives a more precise -value (jamovi: Fig. 29.4; SPSS: Fig. 29.5): the two-tailed -value is , so the one-tailed -value is .
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FIGURE 29.4: jamovi output for the insulation data
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FIGURE 29.5: SPSS output for the insulation data
The software clarifies how the differences have been computed:
Click on the hotspots in the following image, to see how to read the SPSS output.