Question

find a linear regression model
this is a table
Year|1980|'85|'90|'95|'96|'97|'98|'99
spending|4.5|6.6|11.6|12.6|12.7|13.1|12.9|12.4
in billions
using x=0 as 1980, predict the spending for 2006

Answer 1

and write and equation of the line of best fit (round to hundreths)

Answer 2

is this for a stats class?

Answer 3

no its for geometry

Answer 4

well the easiest way is to find the line that goes through the 2 end points
(0,4.5), (19,12.4)
find slope and y_intercept

Answer 5

where did the 19 come from?

Answer 6

year 1999
1999 - 1980 = 19

Answer 7

ok

Answer 8

how does that predict the spending for 2006 though?

Answer 9

once you get the equation of the line
find y when x=26 (2006-1980 = 26)

Answer 10

ok so i got y=.42-4.5

Answer 11

then i make x 26 and have y=.42(26)-4.5

Answer 12

correct
good job

however i wouldn't round the slope so much cause it will effect the answer in next part
slope = .4158

Answer 13

ok

Answer 14

oh wait oops
what is the y_intercept?
its the initial value right?

Answer 15

the y intercept is 4.5

Answer 16

is it positive or negative 4.5

Answer 17

positive

Answer 18

ok, you wrote "-4.5" just checking

Answer 19

thanks

Answer 20

:)