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*Biology Paper 5 tips*

Moi

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PP52
Winter 12
Q 2 - B iii

Which row do we use?
0.05 or 0.01 Probability

The T test shows the difference is Significant.

And the marking scheme states that we need to use row 0.05 Probabilty.... But why??
Doesn't o.o5 mean its Insignificant and due to chance??
 
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Moi

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Salmu alakom guyz ,
In question 3 O/N2007 P5 ,
how to calculate the expected result for the chi square ???
I really don't know how did they calculate it and have got 80 !! + how did they get the degrees of freedom = 2 ??? wont it be 1 ???

Here is the paper :
http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Biology (9700)/9700_w07_qp_5.pdf

and here is the MS :
http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Biology (9700)/9700_w07_ms_5.pdf


Waiting for your help :)
Salmu Alaikom !

For the expected results:
Add the values and divide by the number of values
So (36+90+114)/ 3 = 80 (It's like taking the mean)

The Degrees of Freedom = No. of classes (objects) we are testing Minus 1 (n-1)
We are testing three classes, grazed for two years, ungrazed for 10 years, ungrazed for 30.
These are three things to test
using the formula n-1 -----> 3-1 = 2
2 is the degrees of freedom

Hope it helped :)
 
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here's this q about the chi squared test on/11/53 b) (iii) I'm not being able to solve it can you clear for me how they got the expected value?
 
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here's this q about the chi squared test on/11/53 b) (iii) I'm not being able to solve it can you clear for me how they got the expected value?
They have said in the question that the cats without tails are always heterozygous.. so in cross 1: both parents are heterozygous..
and since the allele without tail is dominant, then each parent has the alleles Rr ..
when both are crossed: Rr x Rr
offsprings will be RR, Rr, Rr, rr
so there is 3/4 chance that the offspring is without a tail..
therefore (3/4) * 112 = 84
112 is the total number of osprings
and there is 1/4 chance that the offspring has tail
(1/4) * 112 = 28
then continue the calculation to find chi square
 
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