[R] Query : Chi Square goodness of fit test
priti desai
priti.desai at kalyptorisk.com
Mon Jul 3 07:26:45 CEST 2006
If we have the data base of frauds given below
no. of frauds = variable
variable
<-c(4,1,6,9,9,10,2,4,8,2,3,0,1,2,3,1,3,4,5,4,4,4,9,5,4,3,11,8,12,3,10,0,
7)
pmf <- dpois(i, lambda, log = FALSE) # prob. mass function of variable
How to apply chi-square goodness of fit to test, Sample coming from
Poisson distribution.
How to calculate observed frequencies & expected frequencies, after that
how to calculate chi 2 test and interpret the result
The formula which I have used & answer which I am getting is as follows,
chisq.test(variable, p=pmf, simulate.p.value =FALSE, correct = FALSE)
Chi-squared test for given probabilities
data: No_of_Frouds
X-squared = 1.043111e+15, df = 32, p-value < 2.2e-16
Warning message:
Chi-squared approximation may be incorrect in: chisq.test(No_of_Frouds,
p = pmf, simulate.p.value = FALSE, correct = FALSE)
But the answer is not correct.
Please suggest me the correct variable, calculations & formula in R.
Awaiting your positive reply.
Regards,
Priti.
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