[BlindRUG] /Chi-square goodness of fit test with R not working

[Godfrey, Jonathan]

Hello Amy,

You didn't need to put in the probabilities as your input is what is used by default. It didn't hurt though. The rest of your code is fine.

I typed chisq.test(c(0,13,17)) and got what I expected.

(-10)^2/10 + 3^2/10 + 7^2/10 = 15.8
The p value is less than 0.0004

I wonder if you are smarter than the person using SPSS? (don't answer that) You must be because you're using R.

Then, to avoid the copy and paste thing, I recommend you get into R markdown as soon as you can.


HTH
Jonathan


-----Original Message-----
From: BlindRUG <blindrug-bounces at nfbnet.org> On Behalf Of Amy Albin via BlindRUG
Sent: Thursday, 7 January 2021 3:45 PM
To: blindrug at nfbnet.org
Cc: Amy Albin <amyralbin at gmail.com>
Subject: [BlindRUG] /Chi-square goodness of fit test with R not working

Hello,

I am working on a data analysis where someone observed drivers and whether they had 0, 1, or 2 hands on the wheel. The data is there were
0 drivers with 0 hands, 13 drivers with 1 hand, and 17 drivers with 2 hands. I am attempting to use R to perform a chi-square goodness of fit test. Here is the result I know it’s supposed to be; this is correct, which someone else generated from IBM-SPSS.
Chi Square = 0.533, DF = 2, P>0.05
Here was my R input.


drivers <- c(0, 13, 17)
res <- chisq.test(drivers, p = c(1/3, 1/3, 1/3)) res


And here is my output from R, which you can see is a completely different chi-square and p value.


	Chi-squared test for given probabilities

data:  drivers
X-squared = 15.8, df = 2, p-value = 0.0003707

What am I doing wrong? Also what is the best way to copy and paste code from my terminal into a word doc or email so I don’t have to retype it like I just did? Thank you.

Best,

Amy Albin
Pronouns: she/her/hers

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