median-median line, scatter plot, trend line
TEKS 8(1)(C), 8(1)(D), 8(1)(G), 8(5)(D), 8(5)(I)
Example Comparing Trend Lines With and Without Outliers
The table and scatter plot show the length of certain models of cars and the miles per gallon they average when driven in the city. The scatter plot suggests a linear association.
a. Draw a trend line and find its equation.
b. Remove the outliers, (212, 17) and (215, 17), from the table. Draw a new trend line for the adjusted data set. Then find the equation for this trend line.
c. How do the outliers affect the position of a trend line? Explain your reasoning by examining the slope of each line.