Chapter 7, Problem 26E

(a)

To determine

To explain does this mean that cell phones are good for your health or not.

Explanation of Solution

A survey of the world’s nations in $2004$ shows a strong positive correlation between percentage of the country using cell phones and life expectancy in years at birth. Thus, it is given that there is positive correlation between percentage of the country using cell phones and life expectancy in years at birth. And if something has a strong correlation then it does not mean it is true. Thus, if the correlation is positive than the claim that cell phones are good for our health can or cannot be true. We cannot say about the statement that it will be true by the above statement.

(b)

To determine

To find out what might explain the strong correlation.

Explanation of Solution

A survey of the world’s nations in $2004$ shows a strong positive correlation between percentage of the country using cell phones and life expectancy in years at birth. Thus, it is given that there is positive correlation between percentage of the country using cell phones and life expectancy in years at birth. This strong relation may be due to the lurking variable of the wealth of the countries. As, the wealthy people can afford their health issues more adequately.