why is the standard deviation of means generally smaller than the standard deviation of the opopulation of individuals

For a research project in a political science course, a student has collected information about the quality of life and the degree of political democracy in 50 nations. specifically, she used infant mortality rates to measure quality of life and the percentage of all adults who are permitted to vote in national elections as a measure of democratization. her hypothesis is that the quality of life is higher in more democratic nations. read this research description carefully. pay attention to the following: how many variables are in this research? what is the scale of the variable for infant mortality? p1c4. what is the dependent variable in this research problem? p1c4. is this research descriptive or inferential? does this research involves single variable analysis or two or more variable analysis?