Biology paper 5 doubts

[Amy Bloom]

Hello peeps.
Here we are with our last paper to complete our A level Biology.
So, to get things in an organised way, i've created this thread, so feel free to post your doubts and so we can help as many ppl as we can.
I shall start with this question.

Good luck everyone!

 

[OakMoon!]

Expected result is more of an assumption. So it can come from anywhere. Usually we find it using probability ratios. And in this case we assume that all kinds of grasslands occur in equal ratio. So 1/3 x 240(total number of rare moths)=80.

 

[Amy Bloom]

Thank you buddy!

 

[Mukit-ul Islam]

hey............are there any good notes for P5 bio? I really need it.

 

[Amy Bloom]

Hello there
Can anyone help me in finding the degrees of freedom for question 3(b)(iv) and show me the way of doing it?
http://www.xtremepapers.com/papers/...and AS Level/Biology (9700)/9700_s09_qp_5.pdf

 

[sagar65265]

Hello there
Can anyone help me in finding the degrees of freedom for question 3(b)(iv) and show me the way of doing it?
http://www.xtremepapers.com/papers/CIE/Cambridge International A and AS Level/Biology (9700)/9700_s09_qp_5.pdf

The question says that hourly samples were made, so for each pH value, there are total 40 values taken.
The number of degrees of freedom for each pH value is (n - 1), so it is totally 40 - 1 - 1 = 38
Therefore, the number of degrees of freedom is 38.

Good Luck for your exams!

 

[Amy Bloom]

The question says that hourly samples were made, so for each pH value, there are total 40 values taken.
The number of degrees of freedom for each pH value is (n - 1), so it is totally 40 - 1 - 1 = 38
Therefore, the number of degrees of freedom is 38.

Good Luck for your exams!

Thank you Sagar, just one more thing, can you explain me how to calculate the degrees of freedom? I mean in terms of a general formula.
Is it that you -1 two times because of 2pH values (i mean 2 samples of data)?

 

[SincerlyMe]

Guys, do you have any advice on what to do the day before the exam, how to prepare and revise?
I kinda had to study for paper 5 all on my own, and I solved all exams from J07 to J12..
Any advice will be appreciated

 

[Amy Bloom]

Guys, do you have any advice on what to do the day before the exam, how to prepare and revise?
I kinda had to study for paper 5 all on my own, and I solved all exams from J07 to J12..
Any advice will be appreciated

Unfortunately i'm in the same situation as yours, but i have hardly any advice to give u, i',m sorry.
Since you've solved the papers i think its enough, just go through them once more. Hey can you help me with the doubt i posted on degree of freedom please? is there any general formula for this???

 

[Mukit-ul Islam]

hey.........i found this somewhere. Hope it helps and all the best for tomorrow!

 

[Amy Bloom]

hey.........i found this somewhere. Hope it helps and all the best for tomorrow!

Sorry i can't view that, can you save on compatibility mode and post back please. I have the old version of word.

 

[Mukit-ul Islam]

Sorry i can't view that, can you save on compatibility mode and post back please. I have the old version of word.

 

[Amy Bloom]

Thanks buddy they are indeed helpful. best of luck to you too.

 

[xyz!]

Can sum1 pls help me out wid d error bars? As in wht do v add and subtract from d main value while drawing error bars? Pls help asap!

 

[Mukit-ul Islam]

Can sum1 pls help me out wid d error bars? As in wht do v add and subtract from d main value while drawing error bars? Pls help asap!

first calculate the mean and standard error. Than we add and subtract 2 times the error from the mean

 

[Amy Bloom]

What are error bars??

 

[xyz!]

first calculate the mean and standard error. Than we add and subtract 2 times the error from the mean

Hey thnx bt if u see 53/o/n/10 the ms says v got to add and subtract 1 and 2 for the error bars...whereas 1 and 2 are the std errors..
From wt i had studied..v hav to multiply by 2 bt den d ms says sumthng diffrnt..pls check it out n tel me..

 

[xyz!]

What are error bars??

Hey its not poss to explain d entire thing lyk dat..pls hav a luk at the ppr which i mentioned..53/o/n/10 u'l cm to noe wt were v tokng abt..
N i'l sugest u to go thru sum revision guide if u hav 1..for better undrstnding..

 

[SincerlyMe]

Hello there
Can anyone help me in finding the degrees of freedom for question 3(b)(iv) and show me the way of doing it?
http://www.xtremepapers.com/papers/CIE/Cambridge International A and AS Level/Biology (9700)/9700_s09_qp_5.pdf

To find the degree of freedom you'll subtract 1 from the number of values you've got and I guess its aim is to reduce the error.
So for this question, you've got 20 values for each pH so this is how you get 38 : (20-1) + (20-1) and I guess if the question was to carry t-test on all 3 pHs you'd do that 3 times and degree of freedom will be a 57 instead
This is how I solved it, and I hope this helps

 

[Amy Bloom]

Hey its not poss to explain d entire thing lyk dat..pls hav a luk at the ppr which i mentioned..53/o/n/10 u'l cm to noe wt were v tokng abt..
N i'l sugest u to go thru sum revision guide if u hav 1..for better undrstnding..

The problem buddy is that i don't have any revision guide regarding s2 because i don't do s2. thanks at least 4 telling me that and good luck