Help using Base SAS procedures

Macro for confidence intervals

Posts: 40

Macro for confidence intervals

I am trying to calculate confidence intervals around teen birth rates by race (WNH, BNH, Asian NH, and Hispanic) for each the largest towns for the state. I will like to create a macro that identifies if the number of teen births for each race group is less than 100 then to calcualte the Confidence Intervals using a poisson distribution if not then a normal distribution where U

Using the following formula when the number of teen births (the numerator) is >= 100:

LCI95 = R - (1.96 * (R/sqrt(Births))

UCI95 = R + (1.96 * (R/sqrt(Births))


R = birth rate

B = number of births


Usingthe following formula when the number of teen births (numerator) is < 100:

So I need to create a file with the poisson values.

LCI95 = R * L

UCI95 = R * U


R = birth rate

L,U = values in the poisson table that correspoins to the number of births.

Any help will be much appreciated!

Super User
Posts: 10,770

Re: Macro for confidence intervals

Check proc univariate option :

CIBASIC , CIPCTLNORMAL  is based on Normal distribution .

CIPCTLDF  is based on Free Distribution i.e. non-parameter method .

Xia Keshan

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