A researcher implemented a study in which it was planned that simple random sampling from a sampling frame would be used, but a systematic sample from the sampling frame is used instead. What has occurred? Select one:
• A random error. • A non-systematic error. • A systematic error. • A sampling frame error. Which of the rules for coding has been violated by the following responses to a question about annual salary? • under $20,000 • $20,000-40,000 • $40,000-60,000 • above $60,000