Cyanide in soil. Environmental Science &  Technology (October 1993) reported on a stud...

Cyanide in soil. Environmental Science &  Technology (October 1993) reported on a study of contaminated soil in the Netherlands. Seventy-two 400-gram soil specimens were sampled, dried, and analyzed for the con taminant cyanide. The cyanide concentration [in milligrams per kilogram (mg/kg) of soil] of each soil specimen was determined by an infrared microscopic method. The sample resulted in a mean cyanide level of  and a standard deviation of s = 80 mg/kg.

a. Test the hypothesis that the true mean cyanide level in soil in the Netherlands exceeds 100 mg/kg. Use α = .10.

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b. Would you reach the same conclusion as in part a if you took α = .05? α = .01? Why can the conclusion of a test change when the value of α is changed?