Answer:
7.67
Step-by-step explanation:
Given the data :
Week_sales_Forecast ___|error|_ |error|²
1 _____15
2 ____ 16
3 ____ 19
4 ____ 18
5 ____ 19 ____ 17 _______ 2____4
6 ____ 20 ___ 18 ________2____4
7 ____ 19 ____19 ________0____0
8 ___ 22 ____ 19 ________3____9
9 ___ 15 ____ 20 ________5___ 25
10 __ 21 _____19 ________ 2 ___ 4
Mean squared error :
(4 + 4 + 0 + 9 + 25 + 4) / 6
= 46 / 6
= 7.666
= 7.67
The slope is 4. It's right there in the problem. The equation underneath that is y=mx + b. M, in this case 4 or 4/1 is the slope. And 5 is the y intercept or where the line crosses the y axis.
The solution is (5, 15)
Multiply the second equation by 2 and then add through.
3x + 2y = 45
8x - 2y = 10
-----------------
11x = 55
x = 5
Then plug in to get the y value
3(5) + 2y = 45
15 + 2y = 45
2y = 30
y = 15
