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Urgent Regression and Correlation help please!!

My class started learning this topic on S1 on Thursday and we have so many home tasks to do and I'm really confused. Please can someone help me with the past paper question in the attachment. I will be so grateful for any help. Thanks in advance to anyone who does!

I've already completed part i) and ii) but I don't understand the rest.

Edit:
I attempted part iii) and I got the equation of the line as
y = 39.345 + -0.1269x

?? I'm so lost :frown:

(edited 8 years ago)

image.jpeg193.7KB

Reply 1

username1732133

Original post by Aty100

Refer to your formula book. See attached. Any problems, post again.

You can check your working here: http://burymathstutor.co.uk/linearRegression.html

correlation and regression.png11.5KB

Reply 2

Aty100

Original post by BuryMathsTutor

Refer to your formula book. See attached. Any problems, post again.

You can check your working here: http://burymathstutor.co.uk/linearRegression.html

I got
y = -72.75 + 2.1115x

That's definitely wrong I just don't understand what I'm doing wrong :frown:

I got
Sxx = 3900
Sxy = 8250
Mean of y= 33
Mean of x= 50

I got b as 2.115
And a as -72.75

:frown:

Reply 3

username1732133

Original post by Aty100

I got
y = -72.75 + 2.1115x

That's definitely wrong I just don't understand what I'm doing wrong :frown:

I got
Sxx = 3900
Sxy = 8250
Mean of y= 33
Mean of x= 50

I got b as 2.115
And a as -72.75

:frown:

What did you get for the various sums? I'll be busy for the next few hours bit if you show more working someone will be able to help.

Reply 4

Gregorius

Original post by Aty100

I got
y = -72.75 + 2.1115x

That's definitely wrong I just don't understand what I'm doing wrong :frown:

I got
Sxx = 3900
Sxy = 8250
Mean of y= 33
Mean of x= 50

I got b as 2.115
And a as -72.75

:frown:

You seem to have gone wrong in your calculation of Sxx and Sxy. Your values of the mean of x and of y are correct. Can you show us how you calculated Sxx and Sxy?