Sample Size Calculator Examples

Example 1

You are about to do the fourth cycle of an audit for compliance to a particular program.
From the previous three cycles, compliance rates have been around 75%, with the desired standard error around 1.6.
There are 100,000 businesses on the frame.

What sample size should you use?


Use...
Confidence Level = 95%
Population = 100,000
Proportion = 0.75
Standard Error = 0.016


Then press calculate
Before Calculate
Image: Example 1, before clicking Calculate

After Calculation
Image: Example 1, after clicking Calculate


Example 2A

You have an allocated budget of $10,000 to determine how satisfied your customers are. You have decided to run a survey. Your database shows that you have 38,000 customers. Last year's survey determined 40% of clients were satisfied.

From your budget you have determined that 5,000 businesses can be approached. Is this too many?

Use...
Confidence Level = 95%
Population = 38,000
Proportion - Let's say 40% again
Sample Size = 5,000

Then press calculate


The estimated Standard Error, in this example is more accurate than it needs to be and therefore we can decrease the sample size with limited impact on the overall accuracy.
In example 2B below, we reduce the sample size to 500.
Before Calculate
Image: Example 2B, before clicking Calculate

After Calculation
Image: Example 2A, after clicking Calculate



Example 2B
Using the same scenario, as in example 2A, but using a sample size of 500.

Use...
Confidence Level = 95%
Population = 38,000
Proportion - Let's say 40% again
Sample Size = 500

Then press calculate

Although the estimated standard error has increased it is sufficient for our survey objectives.

It is important to ensure the sample size is the minimum size that will achieve the desired accuracy.
The decreased sample size will reduce provider burden and survey costs.
Before Calculation
Image: Example 2B, before clicking Calculate

After Calculation
Image: Example 2B, after clicking Calculate



Click here to begin using the Sample Size Calculator...