Question about anomolies

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tazuk
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Question about anomolies

 DO YOU INCLUDE ANOMOLIES IN A GRAPH?
((IVE CONSTRUCTED A SCATCHARD PLOT TO CALCULATE KD AND R0))
 
 

Omai
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I think it dangerous to

I think it dangerous to eliminate outlier data points out of hand. Unless you have a very good reason to eliminate a data point (human error during the taking of that data point), then I think all data points should be included.
 
Omai

tazuk
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 thanks for the reply

 thanks for the reply
As I am producing a graph with the data it is clear that 1 of the points is an annomoly, therefore i didnt include it. Maybe the error should be included, however it causes the graph and results not to fit the trend if i do,
still not decided

Omai
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If you repeat the experiment,

If you repeat the experiment, does the anomoly still show up?
Omai

tazuk
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i didnt actually do the

i didnt actually do the experiment
the data was given to me, and my task is to produce a binding plot, a scatchard plot and a linweaver-burke and then calculate Kd and Ro>> then compare them to each other.
btw how do i calculate R0...I caluclated Kd by  Kd= 1/gradient(slope)
take a quick look if u can.
thanks

Omai
Omai's picture
Can't open the rar file. Here

Can't open the rar file. Here is a good scatchard plot website
www.curvefit.com/scatchard_plots.htm
 
I'm going to move this discussion to the biochemistry forum to get more help.
Omai

tazuk
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 ok i could send you the

 ok i could send you the excel file.
thanks ive looked at that link many times

The FFM
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The slope of a scatchard plot

The slope of a scatchard plot is -1/Kd
If you plot specific activity of the ligand bound recetor[LR]/[ligand] on the Y-axis and specific activity [LR] on the X-axis, the initial concentration of receptors [Ro] is the concentration at which the linear plot intersects the X-axis

tazuk
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 Hi

 Hi
I calculated Kd = -1/ gradient(slope)
-1 / - 0.1279 = 7.81 = Kd
Can i send you the excel file, its in Book 1 above.
Do do i know when it crosses the x-axis do i rearrange the line equation: y= -0.1279x+0.0225 and keep y as 0?
then that would be R0 = 0.1759 (units?)
cheers

The FFM
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I got the xls file thanks

I got the xls file thanks
by your fit with the outlier removed, then yes you have the corect R0 of 0.1759 units (pmol/µg ?)
Was the outlier greater than 2x the standard deviation of the mean for that concentratoin when it was included?  You could present the data with and without it included and explain the criteria you used you exlude it in the relevant plots.
On the Lineweaver-Burk Plot  of 1/[L] on the x axis and 1/[LR] on the Y axis, then the x intercept is -1/Kd and the Y intercept will be 1/R0 (or 1/Bmax)