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

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 >_>

Reply 142

LetoKynes

14

Doughboy

Please explain to me the difference between the two :rolleyes:

Tried doing a little googling..

.. So 95% confidence level is usually equivalent to a signifcance level of 5% ..

http://www.statemaster.com/encyclopedia/Statistical-significance

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

I think I'll just stick with significance level.

Reply 143

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.

Reply 144

antonfigo

3

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 :frown:

Reply 145

letsdothetimewarpagain

19

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 :biggrin:

Reply 146

anyone czn give me a quick summary of dna gel electrophoresis?

Reply 147

Anubis29

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). :yep:

Please correct me if I'm wrong. :P

Reply 148

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). :yep:

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 :frown:

Reply 149

check the link below, posted earlier in this thread by jonathan3909 !

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

Hope it helps.

Reply 150

install a flash player plugin !

Reply 151

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
Not Found
The requested URL /resources/anima...ophoresis.html was not found on this server.

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

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

Reply 152

shuvo_roy

install a flash player plugin !

i have one but i can't upload tsr does not support it

Reply 153

I don't understand what short tandem repeats are and how do the relate to DNA gel electrophoresis?

Reply 154

sandook

doesn not work
Not Found
The requested URL /resources/anima...ophoresis.html was not found on this server.

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

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

sorry my bad........follow the link below.

http://www.dnalc.org/resources/animations/gelelectrophoresis.html

hope it works!

Reply 155

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!

Reply 156

okie ppl just created a rapidshare account for this; i hope am not late :P

http://rapidshare.com/files/388455339/gel_electrophoresis.swf

goodluck everyone

Reply 157

shuvo_roy

sorry my bad........follow the link below.

http://www.dnalc.org/resources/animations/gelelectrophoresis.html

hope it works!

thanks man !!

Reply 158

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 :smile:

Reply 159