### Working with z distribution

Nicotine in cigarettes. To determine whether the mean nicotine content of a brand of cigarettes is greater than the advertised value of 1.4 milligrams, a health advocacy group tests H0: ¹ = 1:4 Ha: ¹ > 1:4 The calculated value of the test statistic is z = 2:42. (a) Is the result significant at the 5% level? (b) Is the res