=+10.93 A hot tub manufacturer advertises that with its heating equipment, a temperature of 1008F can be achieved in at most 15 min. A random sample of 25 tubs is selected, and the time necessary to achieve a 1008F temperature is determined for each tub. The sample average time and sample standard deviation are 17.5 min and 2.2 min, respectively. Does this information cast doubt on the company’s claim? Carry out a test of hypotheses using significance level .05.