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Biology P5 Doubts, Guess Papers, Important Concepts and Leaks.

SB29597

SB29597

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Dukeofwin said:
Apparently this thread also says *Guess Paper* Is it even possible for a P5 to have a guess or was it attention seeking act?
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I asked people to post anything like that over here. And why not, it's only a guess. I also asked for leaks separately. There were a few people last year who had some, unfortunately, nothing substantial has come up till now.:)
 
Waleed Amjad

Waleed Amjad

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Gummy Beat said:
I still don't fully understand the t test and what to do with error bars (what is overlap)
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Hello Gummy Beat!

t-Test is used to test the differences between "TWO MEANS" this means t-test helps us to know whether to accept the "NULL HYPOTHESIS" or not.
Null hypothesis states that the differences in the means we got are not significant and only by chance not by some other factor.
t-Test is used when the data is continuous (Normal Distribution) ( I will attach an image of how a continuous data looks like)

The formula of a t-Test is given in the exam so you do not need to memorize the formula!

After doing the t-Test we get a critical value (or also called as a "t value")

Then to check that the differences in the two means are significant or not , we check the critical value table at probability of 0.05 (5%)

so always when you look at the critical value table directly go to the column of 0.05 probability.

Now choose the degree of freedom ( by subtracting 1 from the total number of means)

Then check your "t-Value" from the given critical values in the column of probability 0.05

if your t value is greater than the the table's value (That is the value lies at the right of the table) then the differences between the means are significant and not by chance so we reject the null hypothesis.

if your t value is less than the the table's value (That is the value lies at the left of the table) then the differences between the means are not significant and by chance so we accept the null hypothesis.

I hope this clears your concept on t-test

This same concept goes for "Chi squared test" but instead of comparing two means, we compare the Test crosses (Differences between observed and expected offspring)


Now for the Error bars, the error values are calculated by finding the value for "Standard Error" (No need to memorize the formula on how to find standard error, the formula is already given in the exam)

If the error bars overlap that means the differences are less likely to be significant
If the error bars do not overlap that means the differences are more likely to be Significant.


Good luck! Best regards, WALEED.
normal67.gif
 
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