An experiment was carried out to investigate the strength variability of pre-stressed, bonded concrete after anchorage failure has occurred, and the results were published in Engineering Structures (June 2013). The maximum strand force, measured in kilonewtons (kN), achieved after anchorage failure for 12 pre-stressed concrete strands is given in the accompanying table. Can you infer that the true variance of the maximum strand forces that occur after anchorage failure is less than 25 kN2? Test using α = .10.

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158.2 161.5 166.5 158.4 159.9 161.9 162.8 161.2 160.1 175.6 168.8 163.7