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Introduction to Curve Fitting: The Line of Best Fit. OBJ: To find the line of best fit for a set of data and find the correlation coefficient for a set of data. This is the key sequence on the calculator: STAT, 1 (for EDIT),1, ENTER, 2, ENTER, 3, ENTER, 4, ENTER, , 2, ENTER, - PowerPoint PPT Presentation
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Introduction to Curve Fitting: The Line of Best Fit
OBJ: To find the line of best fit for a set of data and find the correlation coefficient for a set of data
EX: Find an equation of the line of best fit for the data (1, 2), (2, 3), (3,
5), (4, 5).This is the keysequence on thecalculator: STAT, 1(for EDIT),1, ENTER, 2,ENTER, 3, ENTER, 4,ENTER, , 2, ENTER,3, ENTER, 5, ENTER,5, ENTER, STAT, , 4,ENTER.
In order to measure how closely points
tend to cluster about the line of best fit,
statisticians use a correlation
coefficient, denoted r. If the data fits
perfectly on a line with positive slope,
the correlation coefficient is said to be
+ 1. If the data fits perfectly on a line
with negative slope, the correlation
coefficient is said to – 1. If the points
tend not to lie on any line, then the
correlation coefficient is close to 0.
Find the correlation coefficient for the data. This is the key sequence on the calculator: VARS, 5, , , 7, ENTER.EX: For each pair ofvariables, tell whetheryou think thecorrelation is positive,negative, orapproximately zero. Briefly give yourreasons.
• Average dailytemperatureduring January andaverage heating cost in January.
• A person’s income and the value of his or her house.
• The amount of annual taxes a person pays and his or her height.
EX: The table shows statistics forfour NHL career scoring leaders.
• Find the correlation coefficient.
• Find an equation of the line of best fit.
• Bobby Hill played 1063 games. Use the equation of the line of the best fit to predict the number of goals he might have scored.
Games
Played x
Goals
Scored y
1767 801
1311 724
1282 717
696 593