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Edexcel International A Level Biology Unit 6 ( WBI06)- 13th May 2015

Hi guys, seeing that no one has created a thread for this exam already which is in about a month, how are you guys preparing and how ready are you. Which experiment are you expecting to come up as well? :smile:

love to hear your thoughts and some active discussion!

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Sorry you've not had any responses about this. :frown: Are you sure you’ve posted in the right place? Posting in the specific Study Help forum should help get responses. :redface:

I'm going to quote in Puddles the Monkey now so she can move your thread to the right place if it's needed. :h: :yy:

Spoiler

bump?
hey :smile: how are you revising for unit 6?
I feel like I'm really going to mess up the designing the experiment question :s
Original post by hadukilami
hey :smile: how are you revising for unit 6?
I feel like I'm really going to mess up the designing the experiment question :s


haha thats not too bad! I'm worried about the first question, like when they ask the question relating to "explain why". This means i have to read my unit 4 and 5 notes
Hey.. I find that revising for unit 6 is really not easy! We must know all of the practicals from AS and A2 -.- I have been trying to predict which one may come up but its not so easy :/ Although.. I'm pretty sure the respiration experiment won't come up again! It came up in Janurary and also it is the only one to have come up twice already. I hope a nice one comes up, like the Daphnia heart rate experiment or observation of Mitosis :smile:
Original post by Vetstudent2014
Hey.. I find that revising for unit 6 is really not easy! We must know all of the practicals from AS and A2 -.- I have been trying to predict which one may come up but its not so easy :/ Although.. I'm pretty sure the respiration experiment won't come up again! It came up in Janurary and also it is the only one to have come up twice already. I hope a nice one comes up, like the Daphnia heart rate experiment or observation of Mitosis :smile:


yup the co practical is bound to be one of mitosis or daphnia, tensile strength probably. Silly thing is A Level unit 6's have no pattern unlike unit 3 where a pattern is evident
Well.. It is true that there is no pattern for the experiments that come up, but at least the questions they ask are very similar. In fact, some questions have been identical every year. They nearly always ask for a null hypothesis, a table, a graph, give info on a statistical test and ask for conclusions, ask for safety or ethical issues, ask for limitations of your method, etc. Oh and of course that horrible 10 mark question which always comes up about a detailed method for an experiment -.- haha .. I have a bad feeling about it all though tbh :frown:
It certainly is daunting, but I think for unit 6, you need technique and good writing practice. And ofcourse, knowing all the AS and A2 practicals on your finger tips. Heres the thread for IAL units and 4. http://www.thestudentroom.co.uk/showthread.php?t=3234973
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Avatar for Navo D.
Navo D.
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Is Q1 not following a pattern? :eek: I remember Bio 3 did
Hey :smile: , how do you know whether you have to say "no significant correlation" or "no significant difference" in the null hypothesis? i seem to always be using the wrong one.. :/
Original post by Navo D.
Is Q1 not following a pattern? :eek: I remember Bio 3 did


i know sadly there is no pattern! did you see any pattern for q3?
Original post by hadukilami
Hey :smile: , how do you know whether you have to say "no significant correlation" or "no significant difference" in the null hypothesis? i seem to always be using the wrong one.. :/


Well I usually check what test they say is being done in the next part of that question (I think part (d)). If it's a spearman rank test then I say correlation and if it's t-test or u-test then I say difference. This has worked for me so far in the papers I've done.


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Original post by jshah1997
Well I usually check what test they say is being done in the next part of that question (I think part (d)). If it's a spearman rank test then I say correlation and if it's t-test or u-test then I say difference. This has worked for me so far in the papers I've done.


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yup you are absolutely correct!
when a question asks you to outline a suitable sampling technique, how do you know whether to use random or systematic sampling?
Most of the time you use random sampling for example if you're measuring the distribution/percentage cover of a certain plant or the distribution of a certain insect species which might be dependant on light intensity or temperature
but if in some rare cases you need to find whether the distribution changes in one direction so eg Does the distribution of beachgrass in sand dunes change as you go further away from the sea ? then you use a systematic sampling technique like a belt transect

It's easy to remember if you think that systematic is about a variable changing in one direction
whereas random is just randomly in space using random coordinates and quadrants
Original post by hadukilami
Hey :smile: , how do you know whether you have to say "no significant correlation" or "no significant difference" in the null hypothesis? i seem to always be using the wrong one.. :/


It always depends on the hypothesis
some are trying to find whether the dependent variable increases or decreases ad the independent variable increases
and example could be does Temperature affect Development
so as temperature increases does the percentage hatch rate of brine shrimp increases?
That's correlation so you use spearman rank

difference is when the independent variable is either absent or present, it's not increasing
so does listening to music cause students to have higher/lower results?
listening to music: 10/20
not listening to music: 16/20
and then you use the stats test for difference, because you're not looking for a correlation but just for a difference between two groups

It's hard sometimes to see what it is but you can always just base your answer on what test they use
U/ T= difference
Spearman= correlation
X^2 = comparing expected vs results obtained :smile:
I am worried as oh my god.
I was just reading the things that might be relevant to the Unit 6 experiments, now, I am doomed
Original post by angelonm
Most of the time you use random sampling for example if you're measuring the distribution/percentage cover of a certain plant or the distribution of a certain insect species which might be dependant on light intensity or temperature
but if in some rare cases you need to find whether the distribution changes in one direction so eg Does the distribution of beachgrass in sand dunes change as you go further away from the sea ? then you use a systematic sampling technique like a belt transect

It's easy to remember if you think that systematic is about a variable changing in one direction
whereas random is just randomly in space using random coordinates and quadrants


Thank you!
Original post by maria1607
Thank you!


no problem :smile:

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