<PRE><B>Question 522945</B>
A sample of consumers was surveyed regarding their visits to a computer chain store and if the store was conveniently located.  The following table summarizes the results of that survey:
	
Visits	    Convenient	Not Convenient  Totals
   Often	         60	   20	         80
   Occasional	25	   35	         60
   Never	          5	   50	         55
Column Totals	90	   105	         195

a.	What is this table called: A contingency table.
-------------------------------
b.	Are frequency of visits and convenience independent or related?  Explain your answer.
P(often) = 80/195 ; P(convenient) = 90/195
P(often)*P(confenient) = 0.1893
P(often | convenient) = 60/90 = 2/3 
Since P(oft | conven) is not equal to P(oft)*P(conven) 
they are dependent factors.
-------------------------------------------------------------- 
  
What is the probability of a survey respondent being convenient to a store?
P(convenient+ = 90/195
-----------------------------
c.	What is the probability of a survey respondent being not convenient to a store and never visiting a store in the chain?
P(not convenient AND never visiting) = P(con | never)*P(never)
= 5/55 * 55/195 = 5/195
===========================
Cheers,
Stan H.
================================ 
</PRE>