E.canisinfection is a tick-borne disease of dogs that is sometimes contracted by humans. Among infected humans,the distribution of white blood cell counts has an unknown meanJland a standard deviationu.In the general population, the mean white blood cell count is 7250/mm3[13].Itis believed that persons infected withE.canismust on average have lower white blood cell counts.

(a) What are the null and alternative hypotheses for a one-sided test?

(b) For a sample of15infected persons,the mean white blood cell count isx= 4767/mm3and the standard deviationiss=3204/mm3[14]. Conduct the test at thea= 0.05 level. d=14

(c) What do you conclude?