[R] cochran-grubbs tests results

[miguelgonzalez]

Hello, 

I'm new in this R world and I don't know much about statistics, but now I
have to analize some data and I've got some first queries yet:

I have 5 sets of area mesures and each set has 5 repetitions.
My first step is to check data looking for outliers. I've used the outliers
package. I have to use the cochran test and the grubbs test in case I find
any outlier. The problem is that I don't know how to interpret the results.
Cochran test finds an outlier among variances. Grubbs test finds an outlier
within the set of measures wich corresponds to the variance that is an
outlier. I repeat the Cochran test discarding that measure. And it finds a
new outlier and so on. This is what I've done first:

---------------------------------------------------------------------
> varianza
[1] 9.979937e-07 1.131360e-07 4.140418e-06 2.184604e-07 3.662077e-07
> data1<-c(rep(4,5))
> cochran.test(varianza, data1, inlying = FALSE)

        Cochran test for outlying variance

data:  varianza 
C = 0.7094, df = 4, k = 5, p-value = 0.007645
alternative hypothesis: Group 3 has outlying variance 
sample estimates:
           1            2            3            4            5 
9.979937e-07 1.131360e-07 4.140418e-06 2.184604e-07 3.662077e-07   
--------------------------------------------------------------------------------

It would be really helpful if someone could tell me what C, df, K and
p-value mean. 
Besides, I don't know if alternative hypothesis (in the grubbs test) means
that the highest value is an outlier to be discarded or just the worst
value, but not necessarily to be discarded.

----------------------------------------------------------------------------
> grubbs.test(serie3, type = 10, opposite = FALSE, two.sided = FALSE) 

        Grubbs test for one outlier

data:  serie3 
G = 1.3384, U = 0.2039, p-value = 0.2155
alternative hypothesis: highest value 0.238877332 is an outlier 
-----------------------------------------------------------------------------

As you see I'm quite lost. 
Thank you in advance and I'll keep trying.

Gracias
 
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