Error in sum(x) : invalid 'type' (character) of argument

[Phoenix]

Hi,

I'm trying to run chi-square the frequency of four groups (Improved, negatively maintained, positively maintained and declined).

> table (Group4_subset$Mood.Change)

      Declined       Improved Neg_maintained Pos_maintained 
             3             57             35             53 

I've tried running:

> chisq.test(Group4_subset$Mood.Change, correct=FALSE)

But get this error:

Error in sum(x) : invalid 'type' (character) of argument

How can I get around this?

Many thanks in advance!
Phoenix

[nirgrahamuk]

I'm thinking you intend:

chisq.test(table(Group4_subset$Mood.Change), correct=FALSE)

[georgemsavva]

Looking at the documentation for chisq.test(), you need to pass it either the contingency table or two factors to be compared. So you can pass it the one-way table you created to test the null hypothesis that the four groups are equally large. But is this really what you are trying to do?

[Phoenix]

Hi,

Thank you for your input, it is greatly appreciated!
I have another question, when creating a contingency table prior to performing other chi-square or fisher tests the outputted table never looks like the examples I've seen, I was just wondering if this is an issue?

For example:

> table(Group2_subset$Mood.Change, Group2_subset$Viewed.With)

                      Alone    Someone
  Improved       45     12       0
  Neg_maintained 28      5       2

I'm not too sure what the 48 and 28 means and if these seemingly irrelevant numbers are included in my chi-square/fisher calculations?

Thanks,
Phoenix

[nirgrahamuk]

I see 28 but not 48 ?

Viewed.With probably has na values.
Add the useNA="always" parameter to the table call.