Line of Best Fit

1
Line of Best Fit
What is the purpose of a best-fitting line?
2
Getting Ready
Go to Y menu and clear out any equations.
3
Getting Ready
Clear old data by going to STAT and then ClrList
4
Entering the Data
Go to STAT and then Edit
Fill in L1 and L2 with data
5
Making the Scatter Plot
Go to STAT PLOT
Choose Plot 1
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Making the Scatter Plot
Set up the following screen
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Making the Scatter Plot
Set up an appropriate WINDOW
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Making the Scatter Plot
Press GRAPH
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Finding the Line of Best Fit
Press STAT then arrow over to CALC
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Finding the Line of Best Fit
Choose LinReg(ax b), then press ENTER
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Viewing the Line of Best Fit
Press Y, VARS, and then choose Statistics.
Next, arrow over to EQ and choose RegEQ
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Viewing the Line of Best Fit
Press Graph
13
Making Predictions

• Use the graph or the equation of the line
• of best fit to predict what y would equal
• when x 8, 12, and 15.

14
Data Sets

• Choose a data set
• Median Household Income
• Year 1970 1975 1980 1985
  1995 2003
• Income 36,000 36,500 39,000 39,900 42,000
  44,000
• Female Earnings
• Year 1970 1975 1980 1985
  1995 2003
• Income 22,000 23,000 25,000 27,000 28,000
  31,000
• Male Earnings
• Year 1970 1975 1980 1985
  1995 2003
• Income 38,000 40,000 40,500 40,750 39,000
  42,000

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