Scatter Plot and Line of Best Fit

Scatter Plots and Line of Best FIt

​

Scatter Plot

a type of graph to display data.

​Positive
Negative
No correlation (no association)

​Three Types of Correlation

Multiple Choice

What type of correlation does this scatter plot show?

• positive

• negative

• no correlation

• nonlinear association

Multiple Choice

What type of correlation does this graph have?

• positive

• negative

• no correlation

• non - linear correlation

Multiple Choice

What type of correlation does this graph have?

• Negative

• no association

• positive

Multiple Choice

What type of correlation does this scatterplot have?

• Positive association

• Negative association

• No association

Line of Best Fit

• line through a scatter plot of data points that best expresses the relationship between those points. 

• can use the line of best fit to predict what could happen

• The line of best fit should be in the middle of the points

Multiple Choice

Is this line an accurate line estimate of best fit for the data?

• Yes

• No

Multiple Choice

Which of the following lines represents the line of best fit for the scatter plot?

• A
• B
• C
• D

Using Line of Best Fit to Make Predictions

• Based on the line of best fit

• how many points did someone who player 8 minutes score?

Multiple Choice

A small theme park is trying to determine the number of guests they should expect on a weekend, based on the temperature outside.  Based on the trend line, about how many guests should be expected if the temperature is around 80°?

*note: you can zoom in if you need to see better.

• 8,300
• 8
• 7,300
• 9,300

Multiple Choice

The scatter plot shows the relationship between the number of chapters and the total number of pages for several books.  Use the trend line to predict how many chapters would be in a book with 180 pages. 
*note: you can zoom in if you need to see better.

• 12 chapters
• 15 chapters
• 18 chapters
• 21 chapters

Writing an equation for the line of best fit.

• Find the y intercept. It is your b.

      
  

• Find the slope. It is your m.

  • NOTE - Pay close attention to the scale of the x and y axis.

    Count based on the scale, not just the amount of boxes.

• Plug it into y =mx + b

  
  

Multiple Choice

The graph above shows a line of best fit for data collected on the distance bicyclists have remaining in relation to the amount of time they have been riding.  What is the equation of the line of best fit?

*note: you can zoom in if you need to see better.

• y = -25x + 170
• y = 25x + 170
• y = -(5/8) x + 170
• y = (5/8) x + 170

Multiple Choice

The graph shows a line of best fit for data collected on the price of a unit in relation to the number of units sold.  What is the equation of the line of best fit?

*note: you can zoom in if you need to see better.

• y = - (1/2) x + 10
• y = - 2x + 40

• y = - (1/2) x + 40
• y = - 2x + 10

Correlation Coefficient (r-value)

A number between the values of -1 and 1 that indicates how well a regression equation truly represents a data set.

Multiple Choice

What is the correlation coefficient?

*Note: you can zoom in on the image.

• 0.9938

• -0.9969

• -18.8333

• 328.417

Interpret the slope & y-intercept.

Slope = Change in y over change in x

What does the slope mean?
"expected change in per one "



y-intercept: Where graph crosses y-axis
The value of y when x=0 . (0, )

What does the y-intercept mean?
"at zero the is expected to be "

Fill in the Blanks

What is the equation of the line of best fit?

*Note: you can zoom in to better view the graph.

Fill in the Blanks

Explain what the slope means for the scenario.

*Note: you can zoom in to better view the graph.

Fill in the Blanks

Explain what the y-intercept means for the scenario.

*Note: you can zoom in to better view the graph.

Open Ended

Tell me how you feel about this content in at least one complete sentence.

When you're done, look over your Desmos Scatter Plot Project

& go through the rubric your teacher will hand out to check off the requirements.