In: Statistics and Probability
Suppose you are interested in examining whether intellect is
related to income. Specifically,
you hypothesize that the higher an individual’s IQ is, the more
money s/he is likely to make. In
other words, this hypothesis suggests that IQ (“IQ”) has a positive
effect on income (“Income”).
You have collected the following data from n = 6 respondents
(“Income” is measured in
thousands):
Observation. IQ Income
1 120 55
2 145 120
3 98 38
4 104 45
5 167 95
6 112 40
a. With these data, estimate and for a linear regression model
(hint: make sure to identify
the dependent and independent variables consistent with the above
theory). Write a
sentence or two interpreting these coefficients. Be sure to use the
regression aid sheet.
IQ is independent varibale
income is dependent variable
ΣX | ΣY | Σ(x-x̅)² | Σ(y-ȳ)² | Σ(x-x̅)(y-ȳ) | |
total sum | 746.00 | 285.00 | 3525.33 | 3725.50 | 1654.00 |
mean | 124.33 | 47.50 | SSxx | SSyy | SSxy |
sample size , n = 6
here, x̅ = Σx / n= 124.333
ȳ = Σy/n = 47.500
SSxx = Σ(x-x̅)² = 3525.3333
SSxy= Σ(x-x̅)(y-ȳ) = 1654.0
estimated slope , ß1 = SSxy/SSxx =
1654/3525.3333= 0.46918
intercept,ß0 = y̅-ß1* x̄ = 47.5- (0.4692
)*124.3333= -10.83415
Regression line is, Ŷ= -10.834 +
( 0.469 )*x
slope: 0.469
if IQ score is increased by 1 unit , income will increase by 0.469 units
......
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