A software engineer is asked to analyze the relationship between the number of defects found...

A scatter diagram is the appropriate tool for analyzing the relationship between the number of defects found and the complexity of various software applications. Scatter diagrams are used to plot pairs of numerical data, with one variable on each axis, to look for a relationship between them. This visual representation helps in identifying patterns or correlations between the two variables, such as whether higher complexity correlates with more defects.