Practise justifying a contextual decision from two categorical variables by comparing conditional purchase proportions and assessing whether the variables are independent.
．A car company is investigating whether offering an optional navigation system in their cars at a lower price would
increase sales of the optional navigation system．The navigation system would give the driver directions to a
destination．
A researcher at the company surveyed a random sample of car owners who owned exactly one of their cars．Some
of the cars already had the optional navigation system，and some did not．The researcher asked the car owners
whether they would purchase the optional navigation system if offered at the lower price when they purchase their
next car．
The researcher found that 60 percent of owners had the optional navigation system．The researcher also found
that 18 percent of owners said，＂No，I would not purchase＂the optional navigation system at the lower price．Six
percent of the owners had a car with the optional navigation system and said，＂No，I would not purchase＂the
optional navigation system at the lower price．The following table summarizes this information．
（d）Consider your previous results．Should the car company offer the optional navigation system at the lower
price？Justify your answer．
Question 4
Begin your response to QUESTION 4 on this page．