On 31/01/2014 12:29 PM, Mathew Nagendran wrote:
Hello everyone. I am quite new to R and I would appreciate some help in figuring out what I am doing wrong.For the following code: > #with cost > > m.control=c(1.45,9.40,9.96,4.2,1.86,0.2) > m.sham=c(3.39,23.94,23.62,10.08,2.99,1.09) > > t.control=function(m, a){(1-exp(-a*m)*(1-(1/30)*m))} > t.sham=function(m, a, d){(1-exp(-a*(1-d)*m)*(1-(1/30)*m))} > > t.sham(2, 2, 0.1) [1] 0.9744979 > t.control(2, 2) [1] 0.9829054 > > #without cost > > m.control=c(1.45,9.40,9.96,4.2,1.86,0.2) > m.sham=c(3.39,23.94,23.62,10.08,2.99,1.09) > > t.control=function(m, a){(1-exp(-a*m))} > t.sham=function(m, a, d){(1-exp(-a*(1-d)*m))} > > t.sham(2, 2, 0.1) [1] 0.9726763 > t.control(2, 2) [1] 0.9816844 As you can see the values I am getting for t.control and t.sham are larger in the "with cost" scenario and this shouldn't be the case. (the cost is 1-1/30*m). Is there something wrong I did when defining t.sham and t.control in the "with cost" section that I am failing to see?
You aren't reading your parentheses correctly. In the first case you're multipling only the exp() part by the cost, so you
are subtracting a smaller number from 1, hence you get a larger result. Duncan Murdoch ______________________________________________ R-help@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.
