The following data have to do with the relationship betweenmaternal smoking (# of cigarettes smoked per day,
which is variable X) and infant birth weight (which is variableY). (?X, ?X2, ?Y, ?Y2, and ?XY havealready been
calculated for you and are shown below in redfont.)
Cigarettes Per Day (X) X2 InfantBirth Weight (Y) Y2 XY
2 4 7.5 56.25 15.0
6 36 7.2 51.84 43.2
10 100 6.9 47.61 69.0
12 144 6.2 38.44 74.4
14 196 5.8 33.64 81.2
?X =44 ?X2=480 ?Y=33.6 ?Y2=227.78 ?XY= 282.8
What is the y-intercept (a) for this data?
| | 6.05 |
| | 6.67 |
| | 7.95 |
| | 8.33 |
| | 57.90 |
| | 5.49 |