LAST QUESTION
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Question

LAST QUESTION 
http://prnt.sc/dk196a

roo777x · Answer

@3mar i found the difference being 12.98, but i cant decide A  B, or C

3mar · Answer

Give me 3 min, please!

roo777x · Answer

sure

3mar · Answer

Thank you.

3mar · Answer

Can you share your works/steps, please?

what did you do to reach such answer?

roo777x · Answer

i subtracted some numbers from the next and found the common difference being 12.98.
like 170.85 - 157.87 = 12.98 and so on

3mar · Answer

Ok.. that is great..

so you can get the next value at 34 ...right?

danjs · Answer

Do you have to figure out the equation for the regression line? or is that given

roo777x · Answer

248.73

roo777x · Answer

the equation is not given @DanJS

3mar · Answer

Yes,,,
so what would you do to get the next 35?

roo777x · Answer

ohh, wait a minute, half of 12.98 is 6.49

3mar · Answer

By the way @Roo777x 
You are answering the question not as it is required!

It requires to do a line regression .... Are you familiar with it?

roo777x · Answer

not really. i really just have my own odd ways of doing things

3mar · Answer

Beside your way, you have to answer the question using the specified way.... try this...fill in the table with the values of x and y and you will see the result at the right! https://www.desmos.com/calculator/izyywvuenv

roo777x · Answer

248.73 + 6.49 = 255.22 - is it right anyhow

3mar · Answer

but what about the way I mentioned above?

roo777x · Answer

i see the graph, i just wouldnt be sure what to plug in that equation afterwards

3mar · Answer

Let me show you....

danjs · Answer

The regression line  
y = a*x + b
$$a=\frac{ \sum y*\sum x^2 - \sum x \sum xy}{ n*\sum x^2-(\sum x)^2 }$$

similar kinda thing for the b

roo777x · Answer

yea that confuses me (all the symbols :(

3mar · Answer

https://www.desmos.com/calculator/qbejueydt9

danjs · Answer

just means summation, add up all y, x^2, xy, x,y,

danjs · Answer

lots of calculating, or use the computer like in th elink

roo777x · Answer

ok thanks @3mar ,i see where its going

roo777x · Answer

thank you both!

3mar · Answer

I thank @DanJS in person as he is more academic and know the basic theories and does not depend on the e-help!

That is the teacher as he should be...

3mar · Answer

How is it for b. please @DanJS ??

danjs · Answer

here is a page about it.. http://www.statisticshowto.com/how-to-find-a-linear-regression-equation/

3mar · Answer

Thank you very much, @DanJS ...
It is really helpful...