Skip to content

Interpretation of t.test results

4 messages · Omar Bahy Badreddin, Fernando Marmolejo Ramos, Timur Shtatland +1 more

Original
Fernando Marmolejo Ramos
# 
Dear Omar

Your t.test is telling that the 2 groups are not different. Now it is not clear
if you want to compute the CI for the difference or for each group. If the
former, then the outputs provides you with that information.

It?d be clearer if you provide the full syntax of your t.test. For example,
let?s suppose I have 2 groups as vectors ?a? and ?b?, they are independent, they
have similar homogeneity, I want to use a two-tailed test, and I want a 95%CI
for the difference, so I type


t.test(a, b, alternative = c("two.sided"), paired = FALSE, var.equal = TRUE,
conf.level = 0.95)

Cheers,

Fer
Greg Snow
# 
Omar,

A detailed interpretation of the results are the subject of more than 1 chapter in most introductory statistics books and the topic of several classes/hours of lecture in a standard introductory statistics class.  Your question suggests that you either skipped your intro stats class, or did not learn/do not remember some very fundamental topics that are essential if you are going to be doing any type of inferential statistics.  You should go back an review those chapters of your stats textbook (or get a new/better text and read those chapters) that cover basic hypothesis tests and the t-test in particular.  There are also various online intro classes/videos that may help.  If you then work through an example both by hand and using t.test in R, then you will be able to see which numbers in the example correspond to which parts of the R output as well as gain a better understanding of where the numbers come from and what the proper interpretation is.

This response may seem a bit harsh, but anything else would be doing you a disservice.  Giving you a brief description without the underlying understanding of what is going on would be like having someone else exercise on your behalf, sure you could say that the exercise equipment is being used, but it would have no beneficial effect on your health/weight/waist size.

--
Gregory (Greg) L. Snow Ph.D.
Statistical Data Center
Intermountain Healthcare
greg.snow at imail.org
801.408.8111