A school is interested in estimating the proportion of students who pass a math test for the classes 8,9, and 10. The school decide to use stratified random sampling and treat each class as a stratum....

I want a clear explanation.Plz, do asap.

Extracted text: A school is interested in estimating the proportion of students who pass a math test for the classes 8,9, and 10. The school decide to use stratified random sampling and treat each class as a stratum. The cost of sampling will not vary from stratum to stratum. The school believes that the proportion of students who pass the exam is 0.3 in each of the three classes ( strata). The school desird o estimate the proportion p with a bound of 0.1 on the error of estimation. Find the sample size n and the allocation that gives this bound. Where N, = 200, N, = 320, and N, = 220. %3D