Ndi Family income and its percentage spent on food in the case of
hundred families gave the following bivariate frequencies
distribution
Food expenditure
Family income (Rs.)
(in %)
200-300 300-400 400-500 500-600 600-700
10-15
3
7
15-20
4
9
4
20-25
7
6
12
5
25-30
3
10
19
8
Obtain the equations of the two lines of regression. Also find the
correlation between food expenditure and family income.

let's cover over the formula of the vertex:

y = a(x – h)^2 + k

in this formula, (h,k) are the vertex, always remember that the positive or negative value of the vertex is based on the sign it has.

for example, if the vertex is -3,-6 then both the x and y value would have the positive sign attached to it and if it were a positive x and y value, then a negative sign would be attached to it.

with that being said, for our problem the x value is a positive one so we are looking for a number with a negative sign next to it, in this case the first and second choice.

however, for the first answer choice it isn't quite part of the formula so we know that the answer choice correctly displays the x value.

to confirm, we can see if the -1 fits correctly with the second answer choice, and as mentioned above a negative number will have a positive sign attached to it. so, for our problem we can see that -1 has been changed to +1, so we can confirm that the second answer choice is correct.

hence, our final answer is y=(x - 1)^2 + 1

add 8+12 to get a simplified answer of 12r-20