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p.33 #14-19, p. 34 #32-34, 45-48. p.33 #14-19, p. 34 #32-34, 45-48. p.33 #14-19, p. 34 #32-34, 45-48. Lesson 1.5 - Scatter Plots and Least-Squares Lines. “Line of Best Fit” “Linear Regression Line” “Least Squares Line”. Three terms that mean the same thing. - PowerPoint PPT Presentation
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p.33 #14-19, p. 34 #32-34, 45-48
p.33 #14-19, p. 34 #32-34, 45-48
p.33 #14-19, p. 34 #32-34, 45-48
Lesson 1.5 - Scatter Plots and Least-Squares Lines
“Line of Best Fit” “Linear Regression Line” “Least Squares Line”
Three terms that mean the same thing
In many real-world problems, you will find data that relate 2 variables such as time and distance or age and height. You can view the relationship between 2 variables with a scatter plot.
There is a correlation between 2 variables when there appears to be a line about which the data points cluster. The diagram below shows some possible correlations.
Finding the Least-Squares Line
A scatter plot can help you see patterns in data involving 2 variables. If you think there maybe a linear correlation between the variables, you can use a calculator to find a linear-regression line, also called a least-squares line, that best fits the data.
STAT (L1, L2)STAT / CALC / LINREG
Find and graph the least-squares line.
Correlation and Prediction
• The correlation coefficient, denoted by r, indicates how closely the data points cluster around the least-squares line.
• The correlation coefficient can vary from -1, which is a perfect fit for a negative correlation, to +1, which is a perfect fit for a positive correlation.
Ex. 2 Olympic Freestyle Swimming Event Data
Each day last week, the manager of a movie theater recorded how many people attended a movie. He also recorded how many bags of popcorn were sold.
1) Is there is a correlation between these two sets of data?
Number of people
attending a movie
Number of bags of
popcorn sold
175 76
100 43
213 101
249 133
362 197
331 185
250 148
y = .62x – 23.46 r = .99
2) Use your regression model to predict the attendance at a movie during which 198 bags of popcorn were sold.
Practice - p. 41 #13-20
Homework
Sheet 1.5ORpp. 42 & 43: Do any two problems from
among #22 to 25
• Quiz Tomorrow on Lessons 1.1 to 1.5