Consider a large number of countries around the world. There is a positive correlation between the number of cell phones per person x and the average life expectancy y. Does this mean that we could increase the life expectancy in Rwanda by shipping cell phones to that country?
A) Yes. The correlation says that as the number of cell phones per person goes up, so does life expectancy.
B) No. If the correlation were negative, we could accept that conclusion, but this correlation is positive.
C) Yes. Positive correlation means that, if we increase x, then y will automatically increase.
D) No. The positive correlation just shows that richer countries have both more cell phones per person and higher life expectancies.
E) It makes no sense to calculate correlation between these variables.

Question

Quizplus · Accepted Answer

The positive correlation between the number of cell phones per person and life expectancy does not necessarily imply a causal relationship between the two variables. It may be the case that richer countries have both more cell phones per person and higher life expectancies due to various other factors such as better healthcare, education, and infrastructure. Therefore, simply shipping cell phones to a country like Rwanda may not necessarily increase life expectancy without addressing the underlying factors that contribute to the country's lower life expectancy.

Consider a Large Number of Countries Around the World