Attempts Average / 3 4. Gravetter/Wallnau/Forzano, Essentials - Chapter 9 - End-of-chapter question 5 The following sample of n = 5 scores was obtained from a population with unknown parameters. Scores: 20, 25, 30, 20, 30 Compute the sample mean and variance. (Note: These are descriptive values that summarize the sample data.) (Round your answers to the decimal places.) M = $2 = Compute the estimated standard error for M. (Note: This is an inferential value that describes how accurately the sample mean represents the unknown population mean.) SM = Grade It Now Save & Continue