Title: Ensuring Validity in Research Design: The Importance of Sample Size and Study Design Answer: What is the process for ensuring an adequate and proper sample size for a study? The sample size is a crucial aspect of any research study

Post your answer to 1 of the 3 questions with explanation and details. Please follow the Community Café Guidelines for participating in the Community Café. 
What is the process for ensuring an adequate and proper sample size for a study? 
What are disadvantages of a convenience sample?
What are three disadvantages to an observational study design?