BWhen the y-values increase as the x-values increase, the scatter plot shows a positive association.
AExample Graph:
BPositive association
Practice makes perfect
We want to create a scatter plot that shows the associations between two data sets. Let's start by looking at the sheet of paper from the graphic novel!
We can see on the diagram that one data set represents the year and the second data set represents the average price of going to the movies. To draw a scatter plot, we need to represent the data as ordered pairs (x,y), where x is the year and y is the average price of going to the movies.
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(1996,4.42) & (1997,4.59) (1998,4.69) & (1999,5.08) (2000,5.39) & (2001,5.66) (2002,5.81) & (2003,6.03) (2004,6.21) & (2005,6.41) (2006, 6.55) & (2007, 6.88)
Now, we can graph the ordered pairs on a coordinate plane. Remember that the values for the horizontal axis start with the year 1995.
We want to know whether the scatter plot from Part A shows a positive,negative, or no association. To do so, we can start by reviewing different patterns of associations between two data sets that can be shown using scatter plots.
Notice that we can use the shape of the distribution of a scatter plot to determine the type of the association. Let's now look at the scatter plot from Part A!
We can see that the points lie close to a line. As the year increases, the average price of going to the movies also increases. This means that the slope of the line is positive. Therefore, the scatter plot shows a positive association.
