Surgical cortex screws come in various sizes, with an outer diameter ranging from 1.5 to 5.5 mm. A manufacturer claims that their cortex screw diameters have a standard deviation of0.01 mm. A surgeon takes a sample to test whether or not this is true.

From their sample of27 screws they get a standard deviation ofs=0.018 mm. Conduct a hypothesis test using a significance level of=0.05.

(a) State the null and alternative hypotheses:

Type "sigma" for, e.g.sigma=1foris equal to 1 ,sigma>1for is greater than 1,sigma<1foris less than 1,sigma not = 1foris not equal to 1).

H0:---------------------H1:------------------------------

(b) The critical values areand. (Enter the smaller of the two values first).

(c) The test value is-------------------------------------

(d) Based on our results, we

A.RejectH0.

B.Do not rejectH0.

(e) The final conclusion is that

A.The actual standard deviation of the screws is most likely different than 1.5 mm

B.The manufacturer's claim is most likely true.