Question

Order the equations below from best to worst in terms of how they best fit the data.
y = -x+15
y = -2x+18
y = -2x+19
y = -3x+23

Answer 1

I think it should be in this order but im not sure and I want to be sure
B,C,A,D\
@Directrix

Answer 2

How did you go about deciding on that answer? @Daniellelovee

Did you use the scatter plot points to crank out a line of best fit?

Just wondering how to begin.

Answer 3

I used the replacing x method like for example first I did x=0 then x=1 etc until I got to 8 and I measure the ones that were the most similar

Answer 4

A line of best fit is a straight line that best represents the data on a scatter plot.

This line may pass through some of the points, none of the points, or all of the points.

Nothing new there.

Answer 5

I'd just try graphing all four and visually gauging which fits the points best. Hopefully it's obvious which is worst and second worst and so on.

Answer 6

What would be cool is to plot the points on Desmos and then superimpose the option equations.

Answer 7

how does that work?

Answer 8

Here is the appearance of the regression line.

Answer 9

Do you agree that option B is the best option?

Answer 10

yes I think it should be in this order but im not sure and I want to be sure
B,C,A,D

Answer 11

Then, second best, I think, is option C with y = -2x + 19.

The slope is the same and the y-intercept changes by only one.

Answer 12

and then I thought A

Answer 13

Looking at A and D, D has a slope of -3 and A has a slope of -1.

Both are one-off from the slope of -2. So, I have to think.

I think we should graph each of those and the regression line on the same set of axes.

Answer 14

i am off to graph.

Answer 15

what I did is used x=0 and I got that 15 is closer to 18 than 23 so that is why I picked A

Answer 16

That's is just a check of one point, though. Check another.

Answer 17

ok

Answer 18

ok

Answer 19

1,14 for A
and for D I got 1,20

Answer 20

Here are the graphs. I need to read the Desmos User Guide to learn to plot points. :)

Answer 21

I think the only way to see which is worse is to graph both and just see which appears to fit the worst. The problem is which is "worse" is kinda pretty opinion based, unless you use residuals or something.

Answer 22

oh wow so actually D was better

Answer 23

I agree.

On the graph, the green line D appears to be 3rd in line.

Answer 24

yeah thank you :)

Answer 25

The blue line y = -x + 15 appears to come in last place.

Answer 26

I'm gonna graph them on the actual given graph with the points.

Answer 27

@Daniellelovee You can decide on the order.

> I'm gonna graph them on the actual given graph with the points.

@agent0smith Would appreciate that.

Answer 28

yeah thank you :)

Answer 29

Pending the work of @agent0smith , I am holding at B,C,D,A

When I studied Geometry, the notion of eyeballing answers and geometrical relations was "beaten" out of me. But, sometimes, eyeballing a non-Geometry problem is a good first strategy.

Answer 30

lol xD

Answer 31

Is the blue line y = -x + 15 ? I don't see its label.

Answer 32

Yeah I forgot to label the last one.

Answer 33

I am back to eyeballing.

B
C
D
A

What do you think about that? @agent0smith @Daniellelovee

Answer 34

I think is correct :)

Answer 35

Yeah I think I'd agree. -x + 15 seems slightly worse than -3x+23

Answer 36

Another vague question, of sorts. We will sink or swim together.

Answer 37

swim together?