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mehwish
Re: mathematics with statistics
thanks jawad now i have a good grasp on the points!
Jawad
Re: mathematics with statistics
Without Control group it is just a “case series”. You may have an interesting Case series but without a comparison group you can NOT draw conclusions.
This issue has very nicely explained in a very interesting story which was published in some Epi book.
"One day when I was a junior medical student, a very important Boston surgeon visited the school and delivered a great treatise on a large number of patients who had undergone successful operations for vascular reconstruction. At the end of the lecture, a young student at the back of the room timidly asked, “Do you have any controls?” Well the great surgeon drew himself up to his full height, hit the desk, and said, “Do you mean did I not operate on half of the patients?” The hall grew very quiet then. The voice at the back of the room hesitantly replied, “Yes, that’s what I had in mind.” Then the visitor’s fist really came down as he thundered, “Of course not. That would have doomed half of them to their death.” God, it was quiet then, and one could scarcely hear the small voice ask, “Which half?”
mehwish
Re: mathematics with statistics
thanks!
chameed
Re: Re: mathematics with statistics
quote:
mehwish wrote:
you gave me the meaning of those two terms. i was looking for a descrpitive answer. can both have a control group? if yes then can a study which is conducted without the use of a control group be described as an experiment? i would appreciate an early answer
Can both have a control group? The answer is yes and no. Its up to you. For example, in experimental studies, if you are testing a new medication vs placebo, then placebo group would be control group but you could do the study without placebo group. Same for observational studies.
[Edited by chameed on 03-09-2005 at 07:19 PM GMT]
mehwish
Re: mathematics with statistics
you gave me the meaning of those two terms. i was looking for a descrpitive answer. can both have a control group? if yes then can a study which is conducted without the use of a control group be described as an experiment? i would appreciate an early answer
