1 The personnel director of a large corporation determines t

1.) The personnel director of a large corporation determines the keyboarding speeds, on certain standard materials, of a random sample of secretaries from her company. She wishes to test the hypothesis that the mean for her population is equal to 50 words per minute, the national norm for secretaries on these materials. Explain in general terms the logic and procedures for testing her hypothesis.

2.) Suppose that the personnel director in Problem 1 wants to know whether the key-boarding speed of secretaries at her company is different from the national mean of 50.
(a) State H0
(b) Which form of H1 is appropriate in this instance—directional or nondirectional? (Explain.)
(c) State H1.
(d) Specify the critical values, z.05 and z.01.

3.) Let say the personnel director in Problem 1 obtained Xbar=48 based on a sample of size 36. Further suppose that =10,= .05, and a two-tailed test is conducted.
(a) Calculate xbar.

(b) Calculate z.

(c) What is the probability associated with this test statistic?
(d) What statistical decision does the personnel director make? (Explain.)
(e) What is her substantive conclusion?

Solution