Omeprazole How Long It Takes To Work

Simple Random Sampling: Estimators and Variances

ESTIMADORES DE LOS PARÁMETROS

Nos vamos a restringir a tres tipos de parámetros: el total
poblacional de una variable X:

la
media
poblacional de esta misma variable:

y la
proporción
de la población que pertenece a un grupo determinado:

donde
es una variable indicadora that takes value 1 if the unit has selected the property and is set to 0 if you do not have.

Estimates are:
-

TOTAL is the total sample:

-

MEDIA, is the average meustral:

-
SHARE
is the sampling rate:

These estimators are unbiased for the population parameters.

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ESTIMATES OF VARIANCE


Here we show the expression of the variances for the parameters shown above.

variance of the sample mean:

where is the sampling fraction and the quasivariable

sample.
the total sample variance:

Variance ratio:

Therefore the sampling error for each parameter is the square root of the above variances. Addition the estimators are unbiased estimators for the population variances.