Question
Consider the following table of data. x 1 1 2 2 10 y 3 2 3...
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Consider the following table of data. |
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a. Calculate the least squares line and the correlation coefficient.b. Repeat part (a), but this time delete the last point.c. Draw a graph of the data, and use it to explain the dramatic difference between the answers to parts (a) and (b). |
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Homework Answers
Answer #1
a. 
Sum of X = 16
Sum of Y = 20
Mean X = 3.2
Mean Y = 4
Sum of squares (SSX) = 58.8
Sum of products (SP) = 51
Regression Equation = ŷ = bX + a
b = SP/SSX = 51/58.8 =
0.8674
a = MY - bMX = 4 -
(0.87*3.2) = 1.2245
ŷ = 0.8674X + 1.2245
b. 
Sum of X = 6
Sum of Y = 10
Mean X = 1.5
Mean Y = 2.5
Sum of squares (SSX) = 1
Sum of products (SP) = 0
Regression Equation = ŷ = bX + a
b = SP/SSX = 0/1 = 0
a = MY - bMX = 2.5 -
(0*1.5) = 2.5
ŷ = 0X + 2.5
c. With last point graph is 
Without last point graph is
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