Dear R Helpers, I am stuck on some syntax and I thought that I was following one of the examples that I found out there quite faithfully. I just want to know how to do a t test on a single mean for whether or not it is greater than a specific value. So I am using the data set sleep and I want to know if the mean of extra is greater then zero. I was under the impression that the syntax is t.test(sleep$extra,mu=0,"greater") but I get the error message Error in t.test.default(sleep$extra, mu = 0, "greater") : not enough 'y' observations I have tried this on a few other data sets that have more then 20 observations and I get the same error. I looked in the documentation but the examples are for the comparison of two groups, not a single group mean. Any help would be most appreciated. --John J. Sparks, Ph.D.
T test for Single Mean
2 messages · Sparks, John, Bert Gunter
(Re-) Read the docs (e.g. Intro to R, R Language Definition) . ... arguments have to be named! t.test(sleep$extra,mu=0, alt = "greater") ## works -- Bert
On Wed, Jun 19, 2013 at 6:50 AM, Sparks, John James <jspark4 at uic.edu> wrote:
Dear R Helpers, I am stuck on some syntax and I thought that I was following one of the examples that I found out there quite faithfully. I just want to know how to do a t test on a single mean for whether or not it is greater than a specific value. So I am using the data set sleep and I want to know if the mean of extra is greater then zero. I was under the impression that the syntax is t.test(sleep$extra,mu=0,"greater") but I get the error message Error in t.test.default(sleep$extra, mu = 0, "greater") : not enough 'y' observations I have tried this on a few other data sets that have more then 20 observations and I get the same error. I looked in the documentation but the examples are for the comparison of two groups, not a single group mean. Any help would be most appreciated. --John J. Sparks, Ph.D.
______________________________________________ R-help at r-project.org mailing list 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.
Bert Gunter Genentech Nonclinical Biostatistics Internal Contact Info: Phone: 467-7374 Website: http://pharmadevelopment.roche.com/index/pdb/pdb-functional-groups/pdb-biostatistics/pdb-ncb-home.htm