A researcher decided to use a stratified random sampling technique to collect data from the target population. She decided to use age as variable of stratification and created four strata. She has enough financial resource to consider a random sample of size 1000 sampling units. Study the table below and answer the questions that follow.

Division Population size Sample Size sample Mean

Population Variance

Stratum 1 500 100 40 36

Stratum 2 1000 200 50 49

Stratum 3 1500 350 30 64

Stratum 4 2000 350 55 81

Explain the possible rational to use stratified sampling procedure. (3)

Verify if the sample allocation is done according to principles of proportional allocation. If the allocation is not according to the principles of proportional allocation, reallocate it as such. (6)

Reallocate the sample using Nyman Allocation method. (5)

The sample means were calculated according the proportional allocation sample distributions. Estimate the stratified mean and its sampling error. (5)

Estimate the population total and its standard error. (5)