I am actually getting .718. John, I think there is an error in your working in the revision notes. You have (9,800,000-7,840,000) as 196,000, when it should be 1,960,000. Correct me if I’m wrong.

Sir, the question in the revision kit for this chapter.. a) why is the answer : y = 32.84 – 0.0679x and not : y = 32.84 + 0.0679x? for i got a positive answer for b.

Other than that. how do we know how many decimal places should we use in the exams as the b produces the answer of 0.067857142? Same goes to question c) as it results to 0.9554529 (95.5% in percentage) Please help. I’m very confused.

Sorry – it is a typing error, I will have it corrected. (The same example is used in the full Course Notes and lecture, and there it is typed correctly)

ebrahim85 says

wouldn’t coefficient of determination r2= .95*.95=90%

John Moffat says

Yes it will!

(If you watch the main lectures for F2 I explain the coefficient of determination – these revision lectures are simply meant as quick revision)

akshit says

hy,

in question (B) you have given the answer as 0.977 but i am getting it as 95.2

(7*187000)-(2800*420)=133000 (as you stated in the answer

*?[(7*1,400,000)-(2800*2800)]-[(7*26550)-(420*420)]=1396.6 but you wrote 136096

this is leading to a mistake in my calculations,please confirm

thanks

Rachel says

I am actually getting .718. John, I think there is an error in your working in the revision notes. You have (9,800,000-7,840,000) as 196,000, when it should be 1,960,000. Correct me if I’m wrong.

Erica says

Sir, the question in the revision kit for this chapter..

a) why is the answer : y = 32.84 – 0.0679x and not : y = 32.84 + 0.0679x? for i got a positive answer for b.

Other than that. how do we know how many decimal places should we use in the exams as the b produces the answer of 0.067857142? Same goes to question c) as it results to 0.9554529 (95.5% in percentage) Please help. I’m very confused.

John Moffat says

The answer is y = 32.84 + 6.79x

(b is positive)

The answers to all the examples are at the back of the course notes.

The exam will make it clear how many decimal places are required.

Erica says

Yes, I do know b is positive (because that’s what I got) but I don’t get why the equation of y = a+bx that you wrote in bold is y = 32.84 – 0.0679x.

John Moffat says

Where in this lecture have I written that in bold? I cannot see it anywhere!!

Erica says

In the revision notes.

John Moffat says

Now I have found it!

Sorry – it is a typing error, I will have it corrected.

(The same example is used in the full Course Notes and lecture, and there it is typed correctly)

naveedawan says

obviously grate but not full lecture in length

Javon says

its just a revision lecture…the full length lecture is in the “lectures: category

zoubeir says

thanks