A-Level Biology - Spearman's rank correlation coefficient
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- เผยแพร่เมื่อ 8 ก.พ. 2025
- [D Biology Classroom] CAIE A-level biology 9700
What is Spearman's rank correlation coefficient? How to use it for problem-solving?
*** I made a mistake in the numbers: d2 is not 448 but 452. So rs becomes -0.5734. The conclusion remains unchanged. Sorry for the mistake!
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My teacher has been teaching this topic for so long(the past 2 weeks) you explained it more clearly in 4 min.Thank you !
Glad that I can help :)
This is heavennn . seriously you've explained in a way that can not be more good
Thank you for the kind words :)
Your videos helped me with the practicals in AS, and now they're helping me with the P5 in AL. Thank you so much 🙏😭
You are so welcome! All the best for your exam!
I just have to say that I’ve got my p5 mock today and if I hadn’t have found your channel a few days ago I would be DYING right now - so thank you
Glad that I can help :) All the best for your exam!
God bless you David, you clarified the topics very easily.
@@itookapillinibiza1209 you are welcome!
Thank you sooooo much for amazing videos! They are very concise and well-explained :)
Glad you like them!
Thank youuuuuuuuuuuuuuuuu sirrrrrrrrrr you are an awesomeeeeeee bio teacher!!!!!!!!!! Thanks for uploading thisss such great explanation and simplified tough concept
Thanks for the encouraging words!
The best explanation ever!!!
Thank you !
Amazing amazing AMAZING!!!
Thank you :)
CAN U PLS MAKE A VIDEO FOR SAMPLING AS WELL???? PLSSSDDS
ok Let me think of what I can do about it
@@DBiologyClassroom yes please make on random sampling , frame quadrats , line and belt transects and mark release capture
@@harriskhan8146 ok let me plan on this
thanks, this also works great for AS/A level marine science
Good to know that, and thank for watching :)
Thanks! Some other videos denote ranks from highest to lowest but my textbook and your video both denote rank from lowest to highest. I tried both ways and get the same answer so I guess the way you denote rank doesn't matter.
hi, thanks for the input, I have not noticed that!
Can you please confirm if the sum of D² is 448? I followed your question step wise I keep getting 452, ( disclaimer: not very good with the calculator)
Even in the phone I type in
30.25+56.25+9+72.25+30.25
+1+9+36+100+100+8 and it shows 452
However it is,
Thank you very much , only now I understand this
Probably a mistake on their part , most likely they forgot to add one of the fours
Yes, my mistake. I will write about it in the video description. Thanks !
Wow thanks, this was pretty helpful!
Glad that you find it helpful !
One question please... Why did you not subtract 1 from n (in the significance table, n=12-1), as in other tests like chi-test and t-test.
Hi, for this test, n is the sample, not the degree of freedom.
Thank you so much!!
You are welcome!
Thank you!
you are welcome :)
This is great. Thanks. How do you know the level of significance? , is it something that’s given? And also do I need to know these formulas off head, board Aqa
Hi, the level of significance for bio statistics in A level is fixed at 95% unless it is mentioned otherwise in the question.
Formula will be given.
Does this mean that degrees of freedom for this statistical test is just the number of paired data or I'm missing something??😢
The table uses n, which is the number of paired data. It is not the degree of freedom.
Ohhh ok thank you sooo much 🙏
Danke
In one of the papers , they used the the n value in the level of significance table as - half of n ( as it was paired data).....so are we supposed to take n or half of n?
n is number or paired data. So just count the pairs. n for spearman is not the value of all data.
Very helpful!!!
Glad that I can help!
Hey David! I have this query that what if there are only 2 tied scores. How will I be able to rank them. For eg. If both have value of 2 and their ranks are lets say 3 and 4. Then their rank will be average i.e 3.5??
Yes, that's correct
life saver
Glad that I can help
Someone, please HELP!! I don't understand how you rank the data.
hi, u look at the column, the smallest number gets the rank "1", the second smallest gets "2" etc.
@@DBiologyClassroom Yes, I understood that but then when you rank the percentage cover of daisy, shouldn't the second number be 10 instead of 11, also why aren't the 3, 4, 5 quadrats not 4, 4, 4
@@yasiyousif4120 for % cover of daisy, the second number is 1. The 3,4,5 is an explanation, notice that they do become 4,4,4 after you average them.
@@DBiologyClassroom at 2:42, why are the 4,4,4 at quadrats 6,7,8 and not quadrats 3,4,5?
@@yasiyousif4120 quadrats 6,7,8 are 2%. 2% are the 3rd,4th and 5th rank in that row. So they average to 4 in the end. I think you are confused about the quadrat number and the values inside the quadrat.
Do we have to learn the formulas for alevels p4 exam?
You need to know how to use it, but you don't have to memorize the formula.
IIII just wanna say.. I love you
do we have to learn the formula or it will be given in the paper ? Board CIE
Formula will be given
Ok thanks
Is the df 10 here? Why are we using 12
Because in the table it is n, which is number of pairs.
@@DBiologyClassroom so in the exam, the table given will tell us if we need the df or not.?? or when do we have to find the df in the statistical tests??... could you pleaase clarify
@@encodedblack7960 yup. The table will either be n of df. For A level usually Pearson and spearman table given in n.
@@DBiologyClassroom thanks!
When I did the first example my rs value was not 0.445 but i got 0.566. Can anyone help me out?
Hi, I made a mistake, you can refer to the description of the video, your value is correct.
same
Nice
Thank you !
life saver
@@saadamir6899 thanks for your support 🙌🏻