X Y
-5 44
-3 45
- 1 47
1 50
3 53
5 57
rule
∑X=0
∑Y=44+45+47+50+53+57=296
∑XY =-5 * 44-3 * 45- 1 * 47+ 1 * 50+3 * 53+5 * 57 = 92
∑X^2=70
Therefore, according to the regression formula:
A=∑Y / n =296 / 6=49.33
b =∑xy/∑x^2=92/70= 1.3 14
The tropic of cancer is y = 49.33+1.31* x.
The expected sales volume in September is 49.33+1.314 * 7 = 58.5.