The table below gives the age and bone density for five randomly selected women. Using this data, consider the equation of the regression line, yˆ=b0+b1x, for predicting a woman's bone density based on her age. Keep in mind, the correlation coefficient may or may not be statistically significant for the data given. Remember, in practice, it would not be appropriate to use the regression line to make a prediction if the correlation coefficient is not statistically significant.
Age | 37 | 41 | 58 | 61 | 67 |
---|---|---|---|---|---|
Bone Density | 343 | 330 | 318 | 314 | 312 |
Step 1 of 6 : Find the estimated slope. Round your answer to three decimal places.
Step 2 of 6: Enter the estimated y-intercept. Round your answer to three decimal places.
Step 3 of 6: Enter the estimated value of y when x=49. Round your answer to three decimal places.
Step 4 of 6: According to the equation for the regression line, if the value of the independent variable is increased by one unit, what is the change in the dependent vairbale y^? (answer choices bo, b1, x, y)
Step 5 of 6: Determine the value of the dependent variable y^ at x=0. (answer choices bo, b1, x, y)
Step 6 of 6: Enter the value of the coefficient of determination. Round your answer to three decimal places.
Age (X) | Bone Density (Y) | X * Y | X2 | Y2 | |
37 | 343 | 12691 | 1369 | 117649 | |
41 | 330 | 13530 | 1681 | 108900 | |
58 | 318 | 18444 | 3364 | 101124 | |
61 | 314 | 19154 | 3721 | 98596 | |
67 | 312 | 20904 | 4489 | 97344 | |
Total | 264 | 1617 | 84723 | 14624 | 523613 |
Equation of regression line is Ŷ = a + bX
b = -0.956
a =( Σ Y - ( b * Σ X) ) / n
a =( 1617 - ( -0.9559 * 264 ) ) / 5
a = 373.871
Equation of regression line becomes Ŷ = 373.871 - 0.956
X
Slope b = -0.956
Y intercept = a = 373.871
When X = 49
Ŷ = 373.871 + -0.956 X
Ŷ = 373.871 + ( -0.956 * 49 )
Ŷ = 327.027
As variable X increases by 1 unit, corresponding change in Y would be - 0.956
When X = 0
Ŷ = 373.871 + -0.956 X
Ŷ = 373.871 + ( -0.956 * 0 )
Ŷ = 373.871
r = -0.963
Coefficient of Determination
R2 = r2 = 0.927
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