Population estimates. Refer to the previous exercise. One reason to do an audit such as this is to estimate the number of claims that would not be allowed if all claims in a population were examined by experts. We have an estimate of the proportion of claims from each stratum based on our sample. With our simple random sampling of claims from each stratum, we have an unbiased estimate of the corresponding population proportion for each stratum. Therefore, if we take the sample proportions and multiply by the population sizes, we have the estimates that we need. Here are the population sizes for the three strata:
|
Stratum
|
Claims in stratum
|
|
Small
|
3342
|
|
Medium
|
246
|
|
Large
|
58
|
(a) For each stratum, estimate the total number of claims that would not be allowed if all claims in the stratum had been audited.
(b) (Optional) Give margins of error for your estimates.