*Biology Paper 5 tips*

[Dania_Yz]

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

Thankk you soo muchh!! Goodluckk too

 

[Malik777]

validity depends on the type of test. chi-squared or t-test
reliability depends on the number of times the test is conducted
and accuracy depends on instrumentation used during the exp. :')

hope it helps

If I am not wrong, Validity depends upon standard deviataion and T tests and Chi Test is concerned with reliability ? Aint it?

 

[Someone2]

how do u find expected result in ON'11 P53..... Its a bit different from the rest of the papers...

Good luck for 2mrw!! Im scared

 

[Malik777]

I am not gettin' above 19 :'D
hell difficult than Bio P4 :/

how do u find expected result in ON'11 P53..... Its a bit different from the rest of the papers...

Good luck for 2mrw!! Im scared

 

[Alool]

how do u find expected result in ON'11 P53..... Its a bit different from the rest of the papers...

Good luck for 2mrw!! Im scared

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

 

[Dukeofwin]

Someone please describe the T test for me!

 

[Someone2]

I am not gettin' above 19 :'D
hell difficult than Bio P4 :/

ikr!! but thank god it isnt as important as p4... for our overall grade that is.

 

[Someone2]

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

wow... how did u think of that?! mA... Thanx

 

[Someone2]

can someone plz explain how to calibrate eye piece graticule?? using a stage micrometer...

 

[sitooon]

can someone plz explain how to calibrate eye piece graticule?? using a stage micrometer...

You dont need to know this!
Just mention this point .. its not ppr 3 !

 

[boxfire1995]

Someone please describe the T test for me!

T test is a statistical test carried out when youre comparing two means, or to make it easy my teacher said when you get a continuous graph for your data. Im sure you may have come across the formula and are handy with numbers and a calculator, so ill just tell you how to interpret the result.
The probabilities that we look up in the t test are the probability of the null hypothesis being correct. What the null hypothesis really is os that there is NO significant difference between the data. (Just remember the no significant part and just stick it to any statement they give you).
We take the probability of 0.05 as being the critical, that is 5%.
If the value of your t test is grater that the critical value, it represents a probabibility of LESSER than 5% that your null hypothesis is right. And in science, that 5% probability is too low. So what do you do? You reject the null hypothesis. Because the difference is caused by something else, not chance
And vice versa. If your value of t is lesser than the critical value, it represents a probability greater than 5% that null hypothesis is right and any difference is due to chance.
I hope you got it.

 

[Dukeofwin]

T test is a statistical test carried out when youre comparing two means, or to make it easy my teacher said when you get a continuous graph for your data. Im sure you may have come across the formula and are handy with numbers and a calculator, so ill just tell you how to interpret the result.
The probabilities that we look up in the t test are the probability of the null hypothesis being correct. What the null hypothesis really is os that there is NO significant difference between the data. (Just remember the no significant part and just stick it to any statement they give you).
We take the probability of 0.05 as being the critical, that is 5%.
If the value of your t test is grater that the critical value, it represents a probabibility of LESSER than 5% that your null hypothesis is right. And in science, that 5% probability is too low. So what do you do? You reject the null hypothesis. Because the difference is caused by something else, not chance
And vice versa. If your value of t is lesser than the critical value, it represents a probability greater than 5% that null hypothesis is right and any difference is due to chance.
I hope you got it.

Superb, I get it now! Thanks A ton. Could you now please tell me what are values in t test formula?

 

[boxfire1995]

Superb, I get it now! Thanks A ton. Could you now please tell me what are values in t test formula?

Im glad you got it.
You mean you want to know the formula, right?
Its actually (mean of data 1 - mean of data 2)/ underoot(standard deviation of data 1/number of samples + standard deviation of data 2/number of samples) .
Dont worry, they'll give you the formula, you just need to know how to use a calculator.
If ive helped you, brother, please pray that i get good grades In Shaa Allah.

 

[maronamaro]

what does it menas when the marking scheme says the error bars over lap ?

 

[boxfire1995]

what does it menas when the marking scheme says the error bars over lap ?

You do know the range right? For a mean with error, just write the values of the max and minimum. If they are same with some other data, it means there is no significant difference between the two data. If they dont, then there is significant difference, because they dont match.
Do you get it?

 

[Dukeofwin]

Im glad you got it.
You mean you want to know the formula, right?
Its actually (mean of data 1 - mean of data 2)/ underoot(standard deviation of data 1/number of samples + standard deviation of data 2/number of samples) .
Dont worry, they'll give you the formula, you just need to know how to use a calculator.
If ive helped you, brother, please pray that i get good grades In Shaa Allah.

Your help wont go in vain! INSHALLAH you will ace the grades!

 

[boxfire1995]

Your help wont go in vain! INSHALLAH you will ace the grades!

Jazak Allah. In Shaa Allah, all of us will get good grades.

 

[maronamaro]

You do know the range right? For a mean with error, just write the values of the max and minimum. If they are same with some other data, it means there is no significant difference between the two data. If they dont, then there is significant difference, because they dont match.
Do you get it?

yeap sort of :s if the error bars over lap then it means the null hypothesis is right ? andd what does it means when the marking scheme says the range overlaps in the question of why hypothesis is not supported ? THANKS A LOT

 

[Dukeofwin]

Has there been any question to draw graphs and error bars? If yes then please be kind enough to post them. Thanks

 

[boxfire1995]

yeap sort of :s if the error bars over lap then it means the null hypothesis is right ? andd what does it means when the marking scheme says the range overlaps in the question of why hypothesis is not supported ? THANKS A LOT

Im sorry for a late reply.
It depends on the values. You see, in a graph with continuous data, some values may have overlapping bars and some might not. But just know this.
If error bars overlap, no significant difference, if they dont, there is significant difference and null hypothesis will have to be rejected. --> its a rule.