The correct answer is D. Coefficient of rank correlation.
A scatter diagram is a graph that shows the relationship between two variables. The variables are represented by points on the graph, and the points are connected by lines. A frequency distribution is a table that shows the number of times each value of a variable occurs. A two-way table is a table that shows the frequency of each combination of two variables. The coefficient of rank correlation is a measure of the correlation between two variables. It is calculated by comparing the ranks of the values of the two variables.
A scatter diagram is a useful tool for visualizing the relationship between two variables. It can be used to identify the presence of a correlation, the direction of the correlation, and the strength of the correlation. However, a scatter diagram does not provide a quantitative measure of the correlation.
A frequency distribution is a useful tool for summarizing the data for a single variable. It can be used to identify the most common values of the variable, the range of the variable, and the skewness of the variable. However, a frequency distribution does not provide a measure of the correlation between two variables.
A two-way table is a useful tool for summarizing the data for two variables. It can be used to identify the association between the two variables, the direction of the association, and the strength of the association. However, a two-way table does not provide a quantitative measure of the association between the two variables.
The coefficient of rank correlation is a useful tool for measuring the correlation between two variables. It is a measure of the linear relationship between the two variables. The coefficient of rank correlation can be used to identify the presence of a correlation, the direction of the correlation, and the strength of the correlation.