[R] QQplot normally distributed

[Noor.v.d.Assem]

Hi

See the file  http://www.mijnbestand.nl/Bestand-6ZPTBYDLBZQI.txt here .
That file contains the results of a study on breathing resistance in
children with asthma and children with cystic fibrosis to investigate wheter
there is a relationship between breathing resistance and length in each of
the two groups. Consider the cystic fibrosis group.

See the 
http://www.mijnbestand.nl/Bestand-G68PRQKUB4QX.txthttp://www.mijnbestand.nl/Bestand-G68PRQKUB4QX.txt
R-code  for what I have now

I already have respectivly: a) QQplot with best fit line of resistance
against length, b) investigation linear relationship with a t-test, linear
regression line (see QQplot at part A), c) testing with a different test
statistic, and than the two question I find hard:

To perform the tests in parts b and e, it was assumed that the measurement
errors are normally 
   distributed. Test with a suitable QQ-plot whether or not this assumption
is justified.
   Recall that the residuals of a linear regression can be considered as
approximations of the actual 
   measurement errors.

And: What is, based on all your results, your final conclusion about the
relationship between breathing 
     resistance and length?

I think it has to do something with the Central Limit Theorem?


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