Sta301 3rd question solution with explanations

[farukh.javed]

Ages and weights of Lahore city are given in the following table

Ages (X)

17.5

18.2

19.5

21

25

26

28

30

35

40

50

Weights (Y)

35

37

39

35

55

49

74

60

80

60

55

Calculate
X
Y
X2
Y2
XY
17.5
35
306.25
1225
612.5
18.2
37
331.24
1369
673.4
19.5
39
380.25
1521
760.5
21
35
441
1225
735
25
55
625
3025
1375
26
49
676
2401
1274
28
74
784
5476
2072
30
60
900
3600
1800
35
80
1225
6400
2800
40
65
1600
4225
2400
50
55
2500
3025
2750
310.2
584
9768.74
33492
17252.4


i. Simple regression line age on weight.
Age on weight mean X on Y; and we can say regression line as X on Y and formula is X=a+by

ii. Standard error of estimate for this line.
iii. By using the line, estimate the value of weights at the age of 55.
iv. Check, is there significant relation between ages and weights?