For each of 200 randomly selected cities, Pete recorded the number of churches in the city (x) and the number of homicides in the past decade (y). He calculated the linear correlation coefficient and was surprised to find a strong positive linear correlation for the two variables. Does this suggest that building new churches causes an increase in the number of homicides? Why do you think that a strong positive linear correlation coefficient was obtained? Explain your answer with reference to the term lurking variable.