Suppose an engine oil manufacturer wants to verify the viscosity of its premium 30-weight oil. A simple random sample of specimens taken from automobiles running at normal temperatures was obtained. The viscosities observed were as follows:

25 24 21 35 25 25 35 38 32 36 35 29 30 27 28 27 31 32 30 30 Determine if the median viscosity at normal running temperatures is equal to 30 as advertised for the company’s premium 30-weight oil. (Use a = 0.05.)

Computer Software Exercises