Date: Fri, 27 Jun 2003 10:18:19 +0200
Reply-To: Rita Clivio <Clivio@databank.it>
Sender: "SPSSX(r) Discussion" <SPSSX-L@LISTSERV.UGA.EDU>
From: Rita Clivio <Clivio@databank.it>
Subject: Confidence interval of Composite Estimates
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Dear Listers I'd ask your opinion about a statistical problem.
I make an example to clarify the question.
I wish have an estimate on oil consumption (in litre) in a country; I know that in some regions people use more oil than in others.
In any case, I interview a national sample, asking oil monthly consumption.
(a) keep the estimate obtained from the total sample (i.e. average consumption multiplied by consumers percentages ? I can also calculate the confidence interval at a confidence level)
(b) sum the estimate obtained by each region.
Using the second method how I can calculate the confidence interval or the estimate precision of the resulting sum ? Could I think that with (b) I have a compensation between each error estimate ? And which method is better according to you?
Thank you in advance for your kind contribution.