Question

Trend lines! PLEASE help!!

Answer 1

Reposting under the Algebra section. I need help with 7 and 8

Answer 2

do you still need help

Answer 3

Yes. Sorry I had to log off for a bit, but yes I am in desperate need if you are still here

Answer 4

are you allowed to use technology? like a calculator or excel or open office?

Answer 5

I have a graphing calculator, TI-84
I don't think I'm allowed to use excel, open office, etc

Answer 6

ok let's use a TI84 then

Answer 7

Okie, thanks!!

Answer 8

hit the STAT key (under the DEL key)

then hit enter to get into the edit list menu

Answer 9

I have the points entered for #7 already. The years are in L1 and the prices in L2

Answer 10

ok so your data is already inputted, good

Answer 11

now go back to the home screen (2nd -> quit)

then hit the STAT key again, go to the CALC menu (scroll once to the right) and then scroll down to `4:LinReg(ax+b)`

Answer 12

All right, I did that and then entered to "calculate", and I have the results from that

Answer 13

what do you see?

Answer 14

I got
y=ax+b
a=1616.785714
b=-3116482.143

Answer 15

The reason I am confused on this problem is because those values don't seem to match any of the answers

Answer 16

hmm strange how none of the answer choices match

Answer 17

Yeah, that's what I'm confused on, lol!!

Answer 18

I know my teacher made other mistakes on this test, so maybe this is one as well.

Answer 19

ok I've figured it out. It's strange how your teacher went about this way

instead of doing a true regression, she simply picked 2 points. In this case, the first and last points (0,20200) and (60,119000)

the line through those two points is y = 1646.67x + 20200

then you plug in x = 80, since 2020-1940 = 80, to find the estimated median home price in the year 2020

Answer 20

I noticed that each answer choice had a y-intercept of 20200

so that meant that she made x = 0 when the year was 1940

Answer 21

OH! So, just to make sure I understand, if I use the years as "0,1,2,3,4,5,6" instead of "1940,1950,etc" I will calculate the right answer?

Answer 22

more like 0,10,20,30,40,50,60

Answer 23

OH! Okay!!
Thank you so much!! I think I will be able to understand 8 as well. Thank you thank you!!

Answer 24

you're welcome