www.VirtualNerd.com

How Do You Use a Scatter Plot to Find a Positive Correlation?

Draw a scatter plot from the given data. Then determine if there is a positive, negative, or no correlation.

Summary

  1. A correlation is a way of describing how data points are related to each other
  2. Correlations can be positive, negative, or 0
  3. A graph like this, where data are plotted as individual points, is called a scatter plot
  4. A line of fit is a line that best represents the data
  5. Since the slope of the line of fit is positive, the data have a positive correlation

Notes

    1. A correlation is a way of describing how data points are related to each other
    1. If you have a data set and want to find the correlation, the first thing you need to do is plot the points in a scatter plot
    1. Since we have an x and y value for each data point, we can turn them into ordered pairs that we can plot on the graph
    1. The x-value of the first point is 1 and the y-value is 2
    2. So we can make the ordered pair (1,2)
    3. Then we can plot (1,2) on the graph
    1. The x-value of the second point is 2 and the y-value is 3
    2. So we can make the ordered pair (2,3)
    3. Then we can plot (2,3) on the graph
    1. Plotting all the data points will give us a scatter plot
    1. The line of fit for a scatter plot is the line that best represents the data
    1. The line of fit for a scatter plot is the line that best represents the data
    1. Obviously our data doesn't fall on a perfect straight line
    2. But we can use the scatter plot to estimate a line that represents the data the best
    1. A line that goes right through the middle of where most of the points are will represent the data the best
    1. This is a good estimate of a line that could represent the data
    1. A correlation is a way of describing how data points are related to each other
    2. Correlations can be positive, negative, or 0
    1. The slope of our line of fit will tell us whether our correlation is positive, negative, or 0
    1. Our line tilts upwards, so it has a positive slope
    2. On this line, as the x-values increase so do the y-values, which means it has a positive slope
    1. To figure out the correlation of a set of data, just look at the slope of the line of fit
    2. If you have a positive slope, like we do here, you have a positive correlation
    3. If you had a negative slope, you'd have a negative correlation
    4. If you had a horizontal line, so your slope was 0, you'd have no correlation