Scatter Plots! What’s a Scatter Plot? Two sets of data are plotted as ordered pairs in the coordinate plane and show the relationship/correlation between two variables. • The points in a scatter plot often show a pattern, or _________TREND___. • From the pattern or trend you can describe the ________________CORRELATION . Variables The independent variable is located on the ___________X axis. This variable does not depend on the other variable. The dependent variable is located on the ____________Y axis. This variable depends on the other variable. Independent variable: _______________Input (time) Dependent variable: _____________Output (Money) Note: The independent variable comes first in the table of values. Correlation: the relationship between the dependent and independent variables For our purposes and with our data… relationship, trend, and correlation are synonyms. Correlation/Relationship/Trend Positive Correlation: As x increases, y increases Negative Correlation: As x increases, y decreases No Correlation: The variables are not related so they are independent. Correlation/Relationship/Trend Linear Correlation: Looks like a line (there is a constant ratio), can be positive or negative Non-linear Correlation: Data points have a curved pattern/trend Strong Correlation: The data points are close to each other and have a clear pattern/trend. Weak Correlation: The data points are farther apart but still have a pattern/trend. Examples: Describe the correlations in each scatter plot below: --Which variable is the independent variable? --Does Julie’s age depend on how tall she is? --Or does her height depend on how old she is? Example: Julie gathered information about her age and height from the markings on the wall in her house. Age (years) 1 2 3 4 5 6 7 8 Height (cm) 70 82 93 98 106 118 127 135 a) Label the vertical axis. b) Describe the trend in the data. c) In a complete sentence, describe the relationship between Julie’s age and her height..