You may need to use the appropriate appendix table or technology to answer this question. A simple random sample of 80 items resulted in a sample mean of 70. The population standard deviation is = 15. (a) Compute the 95% confidence interval for the population mean. (Round your answers to two decimal places.) to (b) Assume that the same sample mean was obtained from a sample of 160 items. Provide a 95% confidence interval for the population mean. (Round your answers to two decimal places.) to (c) What is the effect of a larger sample size on the interval estimate? A larger sample size provides a larger margin of error. A larger sample size provides a smaller margin of error. A larger sample size does not change the margin of error.