In: Statistics and Probability
July 2019 Day |
Height of Construction (feet) |
18 |
165 |
8 |
60 |
11 |
90 |
4 |
10 |
16 |
145 |
6 |
30 |
13 |
110 |
d. Define Y'20
a)
b)
x | y | (x-x̅)² | (y-ȳ)² | (x-x̅)(y-ȳ) |
18 | 165 | 51.0204 | 6061.7347 | 556.1224 |
8 | 60 | 8.1633 | 736.7347 | 77.5510 |
11 | 90 | 0.0204 | 8.1633 | 0.4082 |
4 | 10 | 47.0204 | 5951.0204 | 528.9796 |
16 | 145 | 26.4490 | 3347.4490 | 297.5510 |
6 | 30 | 23.5918 | 3265.3061 | 277.5510 |
13 | 110 | 4.59 | 522.44898 | 48.9796 |
ΣX | ΣY | Σ(x-x̅)² | Σ(y-ȳ)² | Σ(x-x̅)(y-ȳ) | |
total sum | 76.00 | 610.00 | 160.86 | 19892.86 | 1787.14 |
mean | 10.86 | 87.14 | SSxx | SSyy | SSxy |
sample size , n = 7
here, x̅ = Σx / n= 10.857 ,
ȳ = Σy/n = 87.143
SSxx = Σ(x-x̅)² = 160.8571
SSxy= Σ(x-x̅)(y-ȳ) = 1787.1
estimated slope , ß1 = SSxy/SSxx = 1787.1
/ 160.857 = 11.11012
intercept, ß0 = y̅-ß1* x̄ =
-33.48135
so, regression line is Ŷ =
-33.481 + 11.110
*x
c)
a) Predicted Y at X= 18 is
Ŷ = -33.4813 +
11.1101 *18= 166.501
b) Y18 = observed value of Y at x 18 = 165
d)
Predicted Y at X= 20 is
Ŷ = -33.4813 +
11.1101 *20= 188.721
R²=0.998
99.8% of variation in observation of variable Y is explained by variable X
High values indicates that data is good fit for linear relationship