a toy maker claims his best product has an average lifespan of exactly 18 years. a skeptical product evaluator asks for evidence (data) that might be used to evaluate this claim. the product evaluator was provided data collected from a random sample of 35 people who used the product. using the data, an average product lifespan of 13 years and a standard deviation of 2 years was calculated. select the 99%, confidence interval for the true mean lifespan of this product. a) [-0.8722, 0.8722] b) [12.128, 13.872] c) [17.128, 18.872] d) [11.986, 14.014] e) [12.853, 13.147] f) none of the above