In: Statistics and Probability
A regional planner employed by a public university is studying the demographics of nine counties in the eastern region of an Atlantic seaboard state. She has gathered the following data:
County
County | Median Income | Median Age | Coastal | |
---|---|---|---|---|
A | $48,952 | 48.3 | 1 | |
B | 46,669 | 58.8 | 1 | |
C | 47,780 | 48.0 | 0 | |
D | 46,855 | 39.2 | 1 | |
E | 37,724 | 51.9 | 1 | |
F | 35,414 | 56.2 | 1 | |
G | 34,389 | 49.1 | 0 | |
H | 38,128 | 30.3 | 0 | |
I | 30,384 | 38.9 | 0 |
A.)Use regression analysis to determine the relationship between median income and median age. (Round your answers to 2 decimal places.)
Income=__________+_________Median Age
B.)Interpret the value of the slope in a simple regression equation. (Round your answers to 2 decimal places.)
For each year (increase/decrease) in age, the income increases ____________ on average.
x | y | (x-x̅)² | (y-ȳ)² | (x-x̅)(y-ȳ) |
48.3 | $48,952 | 2.42 | 68104673.20 | 12837.31 |
58.8 | 46,669 | 145.34 | 35635593.53 | 71966.31 |
48 | 47,780 | 1.58 | 50134266.98 | 8890.03 |
39.2 | 46,855 | 56.92 | 37890864.20 | -46440.25 |
51.9 | 37,724 | 26.58 | 8853269.64 | -15340.07 |
56.2 | 35,414 | 89.41 | 27935922.98 | -49976.81 |
49.1 | 34,389 | 5.55 | 39821709.08642 | -14864.6025 |
30.3 | 38,128 | 270.42 | 6612326.53086 | 42285.975 |
38.9 | 30,384 | 61.54 | 106408394.09 | 80918.93 |
ΣX | ΣY | Σ(x-x̅)² | Σ(y-ȳ)² | Σ(x-x̅)(y-ȳ) | |
total sum | 420.70 | 366295.00 | 659.74 | 381397020.22 | 90276.8 |
mean | 46.74 | 40699.44 | SSxx | SSyy | SSxy |
a)
sample size , n = 9
here, x̅ = Σx / n= 46.744 ,
ȳ = Σy/n =
40699.444
SSxx = Σ(x-x̅)² = 659.7422
SSxy= Σ(x-x̅)(y-ȳ) = 90276.8
estimated slope , ß1 = SSxy/SSxx = 90276.8
/ 659.742 = 136.83651
intercept, ß0 = y̅-ß1* x̄ =
34303.09787
so, regression line is Ŷ =
34303.10 + 136.84
*x
B)
For each year (increase) in age, the income increases _____136.84_______ on average.
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