nafishasan60 wrote:
The average age of chairpersons in a large sample of departments at Delhi University is 55. The average age of chairpersons in those same departments 20 years ago was approximately ten years younger. On the basis of such data, it can be concluded that chairpersons in general tend to be older now. Which of the following casts the most doubt on the conclusion drawn above?
a) The dates when the chairpersons assumed their current positions have not been specified.
b) No information is given concerning
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