Recruiting source and successful performance in job

Observed and estimated cell counts
  Unsatisfactory Satisfactory Total
Employee referral 167
(149.9)
85
(102.1)
252
In-store notice 383
(383.2)
261
(260.8)
644
Employment agency 33
(29.8)
17
(20.2)
50
Media announcement 250
(270.1)
204
(183.9)
454
Total 833 567 1400

Are those sample data consistent with a model of independence?

Explain that independence is a population property and would mean that the probability of injury was the same for all groups of skiers. We must use the sample to help assess whether there is independence in the population.

The randomness of the sample data means that the conditional proportions will not be equal even if there was independence in the population.

Independence is an important special case of the model that is worth testing.

A sample of 1,400 store clerks hired during 1979 by a large US retailing chain was selected by researchers who wanted to determine whether the recruiting source for employees is related to whether they perform satisfactorily in their job (determined from supervisor evaluations). Four recruiting sources were defined.