I?m trying to do a t-test, where the null hypothesis for the two data sets has to be: ?the means are the same?/?difference in means is equal to one? Using the t.test function in R I?m able to see that it uses the following ?alternative hypothesis?: alternative hypothesis: true difference in means is not equal to 0 but does not seem to specify null hypothesis. I believe alternative and null hypotheses are different, although I don?t exactly know how. So what should I use for my t-test? Or is t.test ok?
Is there t.test with null hypothesis?
4 messages · Rick Bilonick, Michael Dewey, Matti Viljamaa
You need to include the argument "mu=1" (without parentheses). For example: > t.test(group1,group2, mu=1) for a two-sample independent groups t-test. If you type: > ?t.test you can see the help information for the t.test function. RIck
On 09/08/2016 08:06 AM, Matti Viljamaa wrote:
I?m trying to do a t-test, where the null hypothesis for the two data sets has to be: ?the means are the same?/?difference in means is equal to one? Using the t.test function in R I?m able to see that it uses the following ?alternative hypothesis?: alternative hypothesis: true difference in means is not equal to 0 but does not seem to specify null hypothesis. I believe alternative and null hypotheses are different, although I don?t exactly know how. So what should I use for my t-test? Or is t.test ok?
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Dear Matti
On 08/09/2016 13:06, Matti Viljamaa wrote:
I?m trying to do a t-test, where the null hypothesis for the two data sets has to be: ?the means are the same?/?difference in means is equal to one?
That is two statements not one. Do you mean that your null is that the difference is 1? If so just subtract 1 from all the scores in the group which is predicted to be higher and run the t-test on the resulting scores.
Using the t.test function in R I?m able to see that it uses the following ?alternative hypothesis?: alternative hypothesis: true difference in means is not equal to 0
It means that the null is that the difference is zero.
but does not seem to specify null hypothesis. I believe alternative and null hypotheses are different, although I don?t exactly know how. So what should I use for my t-test? Or is t.test ok?
______________________________________________ R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
On 08 Sep 2016, at 15:48, Michael Dewey <lists at dewey.myzen.co.uk> wrote: Dear Matti On 08/09/2016 13:06, Matti Viljamaa wrote:
I?m trying to do a t-test, where the null hypothesis for the two data sets has to be: ?the means are the same?/?difference in means is equal to one?
That is two statements not one. Do you mean that your null is that the difference is 1? If so just subtract 1 from all the scores in the group which is predicted to be higher and run the t-test on the resulting scores.
Sorry typo, should of course be: ?the means are the same?/?difference in means is equal to zero? so they are synonymous.
Using the t.test function in R I?m able to see that it uses the following ?alternative hypothesis?: alternative hypothesis: true difference in means is not equal to 0
It means that the null is that the difference is zero.
but does not seem to specify null hypothesis. I believe alternative and null hypotheses are different, although I don?t exactly know how. So what should I use for my t-test? Or is t.test ok?
______________________________________________ R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
-- Michael http://www.dewey.myzen.co.uk/home.html