Question

lesson 13: charts and graphs
scatter plots
what is the main purpose of a scatter plot?
a. show a general trend in data points
b. determine a direct relationship between data points
c. identify the relative size of data categories
d. identify how data changes over time

Explanation:

• Option a: A scatter plot can show the general trend (correlation) between two variables' data points, like positive/negative or no trend.
• Option b: Scatter plots show relationships (correlation), not necessarily direct (causation isn't determined by scatter plot alone, but relationship like linear/non - linear is shown). But the main purpose is to see the trend/relationship. However, "direct relationship" is a bit misleading, but among the options, the best fit for scatter plot's purpose (showing trend/relationship between two quantitative variables) is related to showing trend or relationship. Wait, let's analyze each option:
• Option c: Identifying relative size of data categories is for pie charts or bar graphs (for parts - to - whole or comparing categories), not scatter plots (which deal with two quantitative variables).
• Option d: Identifying how data changes over time is for time - series graphs (like line graphs with time on x - axis), not scatter plots (unless time is one variable, but the main purpose of scatter plot is not specifically time - based change, but relationship between two variables).
• Option a: Scatter plots are used to visualize the relationship (trend) between two sets of data points (e.g., positive correlation, negative correlation, no correlation). So it shows the general trend in data points.
• Option b: "Determine a direct relationship" is not accurate as scatter plot shows correlation (relationship), not direct (causal) relationship. So the correct answer is a.

Answer:

a. Show a general trend in data points