Sampling Size Determination

When we conduct a research study many of us have ampoule of question like- How do I conduct this study? Which research approach is appropriate to my study? How I get the review of literature? So on… When it comes to the sample we ask ourselves which type of sample I go with probability or nonprobability and the next question is How many samples will I need to study….! Consulting with a statistician is worthwhile in addressing many issues of study design, but a statistician is not always readily available.