You may need to use the appropriate appendix table or technology to answer this question. The following sample data are from a normal population: 15, 13, 17, 20, 18, 16, 11, 10. (a) What is the point estimate of the population mean? (b) What is the point estimate of the population standard deviation? (Round your answer to three decimal places.) (c) With 95% confidence, what is the margin of error for the estimation of the population mean? (Round your answer to one decimal place.) (d) What is the 95% confidence interval for the population mean? (Round your answer to one decimal place.) to