Data on three variables have been collected for 15 nations as of 2007. The variables are fertility rate (average number of children born to each woman), average life expectancy for females, and percent urban.

Nation Fertility Life Expectancy for Females Percent Urban Niger 7.1 55 17 Cambodia 3.4 65 15 Guatemala 4.4 73 47 Ghana 4.4 59 44 Bolivia 3.7 67 63 Egypt 3.1 73 43 Dominican Republic 2.9 74 65 Mexico 2.4 78 75 Vietnam 2.1 73 27 Turkey 2.2 74 66 United States 2.1 80 79 China 1.6 74 44 United Kingdom 1.8 81 90 Japan 1.3 86 79 Italy1.4 84 68 Source: 2007 World Population Data Sheet. http://www.prb.org/.

a. Compute r and r 2 for each combination of variables.

b. Summarize these relationships in terms of strength and direction.