According to a magazine, the number of stores that a coffee chain operates worldwide between 1999 and 2003 is as follows where x = 0 corresponds to 1999.
Year, x 0 1 2 3 4
Stores, y 2170 3629 4405 5757 7068
(a) Find an equation of the least-squares line for these data
which is y=1192.4x+2221

(b) Use the result of part (a) to estimate the rate at which new stores were opened annually for the period in question.

Question

According to a magazine, the number of stores that a coffee chain operates worldwide between 1999 and 2003 is as follows where x = 0 corresponds to 1999.
Year, x	0	1	2	3	4
Stores, y	2170	3629	4405	5757	7068
(a) Find an equation of the least-squares line for these data
 which is y=1192.4x+2221

(b) Use the result of part (a) to estimate the rate at which new stores were opened annually for the period in question.

pradipgr817 · Answer

You have the answer for part a)?

anonymous · Answer

yes

anonymous · Answer

y=1192.4x+2221

pradipgr817 · Answer

x varies annually so the slope of the curve will give you the rate at which new stores opened.

anonymous · Answer

how do you find that out

pradipgr817 · Answer

In a linear equation rate of change of output is given by the slope. So you have been asked to find the rate
let two values be x1 abd x2
so 
y1=m*x1+c
y2=m*x2+c
now subtract
y2-y1=m(x2-x1)
m=(y2-y1)/(x2-x1); which is rate at which new stores open