# 18/05/10 Edexcel Bio 6(6BI08) watch

1. yeah, mention both. They can't penalize us!
Write something like this:-
1. The t-test value is greater than/less than the critical value at 95% confidence level,
2. State the values X>0.12
3. Therefore, suggesting that we can reject , and say that there is a significant difference between the two means.
2. But you didn't mentioned both?

I think I am getting a difference between this 5% and 95% thing.

Consider the t-test and say that your t-value is bigger than critical value. This means we can reject our null hypothesis.

The null hypothesis now has a 5% chance of being right. We can reject the null hypothesis and be right 95% of the time.

That probably made no sense though >_>
3. (Original post by Doughboy)
Please explain to me the difference between the two
Tried doing a little googling..

.. So 95% confidence level is usually equivalent to a signifcance level of 5% ..
http://www.statemaster.com/encyclope...l-significance

Sigh lol I don't even know anymore, I was always told it was 5% either way

I think I'll just stick with significance level.
4. Guys, the SAFEST THING TO SAY IS:

...at the 5% significance level (being 95% confident).

So here's a model answer for t-test.

1. The calculated t-value is bigger than the critical value
2. Quote figures t-value > crit. value
3. So, at the 5% significance level (being 95% confident) we can reject the null hypothesis
4. And say that there IS a significant difference between the opening angles of lightly shaded wood sorrel and heavily shaded wood sorrel.
5. (Original post by Doughboy)
Lol. Edexcel samples have been known to have errors.

Quote from all papers I have done:

The safest thing to say is 5% confidence level or 5% value. I'll look it up more and come back with an answer.
So does that mean that the question aching my head in the unit 6 chem sample paper had a mistake?

The trans metal question.... in green ions it included cu2+ and then magically it became blue later...

sorry out of topicness....

i'm learning utest ttest wtest correlation and chi2....

also i wonder how many of us will blindly write " since this is greater than the critical value , null hypothesis will be rejected" for the ttest and correlation and chi test.. without knowing **** about statistcs.... sadly , i will be one of them
6. Rightio, no one else respond to each other, I don't care who is making fun of who and who started it, anyone who continues it will be warned. Other than that, carry on
7. anyone czn give me a quick summary of dna gel electrophoresis?
8. (Original post by sandook)
anyone czn give me a quick summary of dna gel electrophoresis?
I'll have a try.

Samples of DNA fragments of different sizes are put into separated wells in an agarose gel in a buffer solution.

A sample with known DNA fragements is also added to one of the wells for comparison.

A electric current is then pass though the apparatus.

The DNA fragments moves at different rates because they carry different charges and are of different sizes. They are all moving towards the positive anode.

When the electrophoresis is almost done(which is shown by a visible dye earlier added with the samples, which moves slightly faster), you can turn off the electricity.

By shining UV light on the gel in the dark, you shall be able to see separated bands representing different DNA fragments(because another dye, which fluorescences in UV light and binds to the DNA is also added to the sample at the beginning).

Please correct me if I'm wrong. :P
9. (Original post by Anubis29)
I've have a try.

Samples of DNA fragments of different sizes are put into separated wells in an agarose gel in a buffer solution.

A sample with known DNA fragements is also added to one of the wells for comparison.

A electric current is then pass though the apparatus.

The DNA fragments moves at different rates because they carry different charges and are of different sizes. They are all moving towards the positive anode.

When the electrophoresis is almost done(which is shown by a visible dye earlier added with the samples, which moves slightly faster), you can turn off the electricity.

By shining UV light on the gel in the dark, you shall be able to see separated bands representing different DNA fragments(because another dye, which fluorescence in UV light and binds to the DNA is also added to the sample at the beginning).

Please correct me if I'm wrong. :P
that sounds correct i guess i just got this flash animation but i dnt know how to upload it the system does not support the file
10. check the link below, posted earlier in this thread by jonathan3909 !

http://www.dnalc.org/resources/anima...ophoresis.html

Hope it helps.
11. install a flash player plugin !
12. (Original post by shuvo_roy)
check the link below, posted earlier in this thread by jonathan3909 !

http://www.dnalc.org/resources/anima...ophoresis.html

Hope it helps.
doesn not work

Apache/1.3.39 Server at proxy-dnalc.org Port 8080

ahhh can u tell me how to upload a .swf file here?
13. (Original post by shuvo_roy)
install a flash player plugin !
i have one but i can't upload tsr does not support it
14. I don't understand what short tandem repeats are and how do the relate to DNA gel electrophoresis?
15. (Original post by sandook)
doesn not work

Apache/1.3.39 Server at proxy-dnalc.org Port 8080

ahhh can u tell me how to upload a .swf file here?

http://www.dnalc.org/resources/anima...ophoresis.html

hope it works!
16. (Original post by Doughboy)
I don't understand what short tandem repeats are and how do the relate to DNA gel electrophoresis?
Short tandem repeats are the mini and micro- satellites that are repeated many times and are the non- coding sequences!

the DNA fragments used in gel electrophoresis contains mostly these mini and micro satellites!
17. okie ppl just created a rapidshare account for this; i hope am not late :P

http://rapidshare.com/files/38845533...rophoresis.swf

goodluck everyone
18. (Original post by shuvo_roy)

http://www.dnalc.org/resources/anima...ophoresis.html

hope it works!
thanks man !!
19. (Original post by shuvo_roy)
Short tandem repeats are the mini and micro- satellites that are repeated many times and are the non- coding sequences!

the DNA fragments used in gel electrophoresis contains mostly these mini and micro satellites!
OK, I still don't get it though.

Dude, you are totally gonna rock this exam
20. Everyone sitting for the exam tomorrow.....Good Luck!

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