Nonlinear Regression Analysis for Biological Experiment

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    Nonlinear Regression
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Discussion Overview

The discussion centers around the analysis of data from a biological experiment investigating the effect of trypsin concentration on the rate of casein hydrolysis. Participants explore methods for analyzing the reliability of results obtained through nonlinear regression, specifically using a third-degree polynomial, and consider alternative models for fitting the data.

Discussion Character

  • Exploratory, Technical explanation, Debate/contested

Main Points Raised

  • The original poster seeks guidance on how to interpret parameters from nonlinear regression analysis to assess the reliability of their results.
  • Some participants suggest that the data could be analyzed using simpler tools, such as a TI-83 calculator, and request the data for further analysis.
  • The original poster provides a dataset detailing trypsin concentration and corresponding mean rates of casein hydrolysis.
  • One participant questions the choice of a third-degree polynomial for fitting the data and proposes the Michaelis-Menten equation as a potentially more suitable model.

Areas of Agreement / Disagreement

There is no consensus on the appropriate model for data fitting, with some participants advocating for the current approach while others suggest alternatives. The discussion remains unresolved regarding the best method for analyzing the results.

Contextual Notes

Participants have not reached an agreement on the assumptions underlying the choice of regression model, and the implications of using different models remain unexplored.

garytse86
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Hello there. I have just finished a biological experiment on "effect of trypsin concentration on rate of casein hydrolysis"
I have already obtained a graph, and I used a program called "Graphpad Prism" to analyse the data usin nonlinear regression (3rd degree polynomial). I have got all the parameters like sy.x, degrees of freedom... But how do I use these parameters to analyse whether my results are reliable, and by varying enzyme concentration results in an increase in rate?

I have also considered Spearman's rank coefficient but this is only for linear relationships. What else can I do to determine whether my results show regression?

Thank you very much.
 
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can someone help?
 
Show us the data

You sound like your in AP Stats still... but really the data should be able to be analyzied with something as simple as a TI-83 + with little problem... If perhaps you showed the data I could further explain how well your data fits your regression line predicted.
 
hello here is the data:

Concentration (%) Mean time (s) Mean rate (s-1) Percentage mean rate (%)
0 0 0 0
0.1 328 0.00304878 27.43902439
0.2 214 0.004672897 42.05607477
0.3 128 0.0078125 70.3125
0.4 130 0.007692308 69.23076923
0.5 98 0.010204082 91.83673469
0.6 98 0.010204082 91.83673469
0.7 100 0.01 90
0.8 96 0.010416667 93.75
0.9 92 0.010869565 97.82608696
1.0 90 0.011111111 100
 
why you fit the data with a 3 degree

why not u fit your data with Michaelis-menten equation?
 

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