A hot tub manufacturer advertises that a water temperature of 100° F can be achieved in 15 minutes or less. A random sample of 25 tubs is selected, and the time necessary to achieve a 100° F temperature is determined for each tub. The sample mean time and sample standard deviation are 17.5 minutes and 2.2 minutes, respectively. Does this information cast doubt on the company’s claim? Carry out a test of hypotheses using significance level 0.05. |

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