10
Chapter 2
Sampling Wizard: Sample Size
Figure 2-4
Sampling Wizard, Sample Size step
This step allows you to specify the number or proportion of unitsto sample within the current
stage. The sample size can be fixed or it can vary across strata. For the pur pose of specifying
sample size, clusters chosenin previous stages canbe used to define strata.
Units. Youcan specify an exact sample size or a proportion of unit sto s ample.
Value. Asingle value isapplied t o all strata. If Counts is selected as the unit metric, you should
enter a positive integer. If Proportions is selected, you should enter a non-negative value.
Unless sampling with replacement,proportion values should also be no greater than 1.
Unequalvalues for strata. Allows you to enter size values on a per-stratumbasis via the Define
Unequal Sizes dialog box.
Readvalues from variable. Allows you to select a numeric variable that contains size values
for strata.
If Proportions is selected, you have the option to set lower and upper bounds on the number of
units sampled.