[R] There is an error when I performed chisquare and postanova test...:(

Michael Dewey lists at dewey.myzen.co.uk
Fri Sep 25 14:24:12 CEST 2015

Dear massmatics

The list has a no homework policy but in this case I feel I can depart 
from that. Have you tried reading the documentation for chisq.test?

On 25/09/2015 12:44, massmatics wrote:
> I am studying for a quiz and while I was solving two problems, an error
> occured.
> a) So the problem is we want to test if the block program makes a difference
> in retention at α = 1%
> (which is the significance level)
> This is the code I used to perform chisquare test.
> My solution:
> blockprogram <- matrix(c(18,15,5,8,4,10,5,7,18,10), nrow=2, byrow=T)
> colnames(blockprogram) <- c("1 yr","2 yr","3 yr","4 yr","5+ yrs")
> rownames(blockprogram) <- c("Non-Block","Block")	
> chisq.test(blockprogram, conf.level=0.99) ==> This is the part where I can't
> run..
> chisq.test(blockprogram, conf.level=0.99)$observed
> chisq.test(blockprogram, conf.level=0.99)$expected
> So my question is is it the *conf.level=0.99* where it is wrongly used?
> b)I was able to run the one way anova but wasn't able to run on the tukey's
> test. I seriously do not know what went wrong... So, this is the original
> problem:
> The data set chicken.csv contains weights of chickens which are given 1 of 3
> different food rations. Perform an ANOVA procedure to determine if the
> weights of the chickens are significantly affected by the food rations they
> are provided. In case a significant effect exists, perform a Tukey HSD
> post-hoc procedure to identify under which ration the chickens will be
> heaviest. Use a 5% level of significance.
> SO here's the code I used to perform:
> chicken <- read.csv("C:/Users/Win/Desktop/chicken.csv")
> attach(chicken)
> anova(lm(chicken$ration~chicken$weight))
> anova.ration <- aov(chicken$ration~chicken$weight)
> *posthoc.ration <- TukeyHSD(anova.ration, 'weight', conf.level=0.95) => This
> is the part where I wasn't able to run :(*
> tapply(ration,weight, mean, na.rm=T)
> plot(posthoc.weight)
> Thanks!
> --
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