The relationship between age (X, in year) and the number of overseas holidays a year (Y) has been studied using simple linear regression sing the following model.
Yi = 0 + 1 Xi + ui
The following table shows the data of age and the number of overseas destinations for a random sample of 20 respondents.
Age (X)
62
57
40
49
67
54
43
65
54
41
No of overseas holiday (Y)
6
5
4
3
5
5
2
6
3
1
Age (X)
44
48
55
60
59
63
69
40
38
52
No of overseas holiday (Y)
3
2
4
5
4
5
4
2
1
3
The summary of the data is as follows where SST is the total sum of squares, SSR is the regression sum of squares.
Xi = 1060, Yi = 73, Xi2 = 57994, Yi2 = 311, XiYi = 4097,
SST = Σ(𝑌𝑖−𝑌̅)2 = 44.55, SSR = Σ(𝑌̂𝑖−𝑌̅)2 = 28.65
a) Find the estimated regression line 𝑌̂𝑖 = b0 + b1 Xi that links the age with the number of overseas holidays in a year.
b) Test whether coefficient b1 is statistically significant or not. Use 5% significant level.
c) Interpret the estimated slope coefficient, b1.
d) Suppose that Ah Huat is 50 years old, predict how many times he has gone overseas for a holiday?
e) Give one quantitative and one qualitative variable that are expected to affect the number of overseas holiday in a year.
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