Question 136315
The management of the corporation looking at training issues are not convinced that they should switch to toutside consultants for all of their training programs. They want to look at how the two groups compared on the pretest. The relevant data are given below. 
.............Population 1.......Population 2
.............Outside Consultant In House trainer 
Sample
Size............... 30.................. 40 
Mean Pretest Scoret 4.8................. 5.2 
StD  Pretest Score. 0.3................. 0.4 
Test to see if there is a mean difference in the pretest scores. Use Alpha 0.05
Ho: u1-u2 = 0
H1: u1-u2 is not zero 
Alpha: 5%
CV: z = +/- 1.96
Comment: I am using z instead of t because the samples are >=30.
What Formula?
z(4.8-5.2) = [(4.8-5.2)-0]/sqrt[s1^2/n1 + s2^2/n2] 
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Cheers,
Stan H.