BEO2255: Applied Statistics for Business Week 3: Simple random stratified random and cluster sampling Tutorial 1. What is meant by random sampling? 2. What are the difficulties associated with selecting a simple random sample 3. State two non-random sampling approaches 4. Distinguish sampling error from non-sampling error and list main non-sampling errors related to data collection 5. What is the difference between sampling with replacement and sampling without replacement? 6. Suppose that 5000 sales invoices are separated into four strata. Stratum 1 contains 50 invoices, stratum 2 contains 500 invoices, stratum 3 contains 1,000 invoices and stratum 4 contains 3,450 invoices. A sample of 500 sales invoices is needed. a. What type of sampling should you do/ why? b. Explain how you would carry out the sampling according to the method stated in (a) c. Why is the sampling in (a) not a simple random sampling 7. Distinguish between stratified and cluster sampling