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Identify Positive and Negative Trends: Mini-Lesson Review

Identify Positive and Negative Trends: Mini-Lesson Review

Identify Positive and Negative Trends: Mini-Lesson Review

Mini Lesson Question

Question #2: Identify Positive and Negative Trends

The scatter plot shows data on weight in pounds ( x ) and fuel efficiency in miles per gallon ( y ) for 13 cars. 

points (2500, 28), (3259,23), (3500,25), (3559,22), (3550,18), (3700,20), (4000,20), (4000,18), (4400,16), (4500,16), (4750, 14), (5250, 12), (5700,15)

Which statement best describes the data?

  1. There appears to be a positive relationship between fuel efficiency and weight. The cars with greater weight tend to have greater efficiency.
  2. There appears to be a positive relationship between fuel efficiency and weight. The cars with greater weight tend to have lesser efficiency.
  3. There appears to be a negative relationship between fuel efficiency and weight. The cars with greater weight tend to have greater efficiency.
  4. There appears to be a negative relationship between fuel efficiency and weight. The cars with greater weight tend to have lesser efficiency.

Identify Positive and Negative Trends 

Scatter plots may have a strong linear trend or a weak linear trend. A strong positive trend means as one variable increases, the other variable increases, A strong negative trend means as one variable increases, the other variable decreases. A weak linear pattern means the points are more scattered.

Three scatter plots. The left graph shows a strong positive linear trend because the points are plotted at higher y-values when the x-values increase, with no outliers. The middle graph shows a strong negative trend because the points are plotted at lower y-values when the x-values increase, with no outliers. And, the right graph shows a weak negative trend because the points are plotted at lower y-values when the x-values increase, but there are several points that do not closely follow that rule.

Try it

Identify Positive and Negative Trends

A scatter plot on the coordinate grid in the first quadrant. The x-axis extends from 0 to 35 and the y-axis extends from 0 to 6.

Does the scatter plot show a positive or negative trend? Is the relationship weak or strong?

Here is how to describe the relationship:

As the xx-values increase, the yy-values decrease. The trend is negative. The relationship is linear, but the points are scattered, so the relationship is weak.

Check Your Understanding

The scatter plot shows the relationship between crocodiles body mass in pounds, xx, and bite force in pounds, yy. Which statement best describes the relationship between body mass and bite force?

Scatter plot showing the relationship between body mass of a crocodile, in pounds, on the x-axis and its bite force, in pounds, on the y-axis.

  1. There appears to be a positive relationship between bite force and body mass. The greater the body mass, the greater the bite force tends to be.

  2. There appears to be a positive relationship between bite force and body mass. The greater the body mass, the lighter the bite force tends to be.

  3. There appears to be a negative relationship between bite force and body mass. The greater the body mass, the greater the bite force tends to be.

  4. There appears to be a negative relationship between bite force and body mass. The greater the body mass, the lighter the bite force tends to be.

There appears to be a positive relationship between bite force and body mass. The greater the body mass, the greater the bite force tends to be.

Check yourself: Looking at the scatter plot, as the body mass of the crocodiles increases, so does the bite force. So there appears to be a positive relationship because both quantities are increasing.

Video: Trends in a Scatter Plot

Khan Academy: More on Scatter Plots

The following video shows how to identify positive and negative trends in a scatter plot.

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