Are you able to use a weighted average to estimate the population average where Stratified random sampling has been implemented? N = 100 has been separated into 2 strata of sizes 30 and 70. Samples of n1=10 and n2=15 are taken from the 2 strata. The sample average in the first sample is 3 and the sample average of the second sample is 4. Estimate the average of the population.