WHAT IS A SCATTER PLOT?
A scatter plot is a graph in which two
sets of data are plotted as ordered
pairs in a coordinate plane.
When Would You Use a Scatter Plot?
Scatter plots are used to investigate a
relationship between two quantities and to
identify the trend in the data set. (negative
correlation, positive correlation, or no
correlation)
The scatter plot at the left shows how more hours of studying results in a higher test score.
This is useful for a student to determine about how many hours to study for a test if he or she wants to achieve a certain score.
HOURS OF STUDY VS. TEST SCORES & RELATION TO REAL LIFE
WHAT DATA IS NECESSARY TO MAKE A SCATTER PLOT?
• MULTIPLE (TWO) SETS OF NUMERICAL DATA
• AN INDEPENDENT VARIABLE
• A DEPENDENT VARIABLE
• IN SOME CASES, AN INDEPENDENT VARIABLE AND DEPENDENT VARIABLE CAN BE INTERCHANGED
Example of a Real Life Scatter Plot
Problem:Identify the correlation of the data. If a woman’s shoe size is 10.5, about how tall in inches would you expect her to be?
ADVANTAGES AND DISADVANTAGES OF USING A
SCATTER PLOT
It can help identify trends in the data by a positive correlation, negative correlation, or no correlation.
Scatter plots show the minimum, maximum, and outlier(s) of the data set.
Advantages Disadvantages• The scatter plot makes it
hard to see the data because there are no graph lines to see exactly where the point is.
• Although a scatter plot can help you see relationships in the data, it is sometimes difficult to tell if the correlation is positive, negative, or if there isn’t one.