Homework help: Is this how CI using t dist are constructed?
I'm trying to replicate some of the examples from my textbook in R (my text uses Minitab). In this problem, I'm trying to construct a 95% confidence interval for these distance measurements [1]:
# Case Study 7.4.1, p. 483 x <- scan()
1: 62 52 68 23 34 45 27 42 83 56 40 12: Read 11 items
alpha<-.95 mean(x) + qt(c((1-alpha)/2, 1-((1-alpha)/2)), df=length(x)-1) * sd(x)
/ sqrt(length(x)) [1] 36.21420 60.51307
Are confidence intervals with the t distribution constructed using this type of equation, or am I overlooking a more concise, 'canned' approach that's already been programmed? Any suggestions on simplifying this? Thanks for all your advice and help. -Kevin [1] An Introduction to Mathematical Statistics and its Applications, fourth ed., Larsen and Marx. Kevin Zembower Internet Services Group manager Center for Communication Programs Bloomberg School of Public Health Johns Hopkins University 111 Market Place, Suite 310 Baltimore, Maryland 21202 410-659-6139