1. Using the t-table, give the confidence coefficients (t-value) for each of the following: a. n=12, 99% confidence b. n=23, 95% confidence 2. Assuming that the samples come from normal distributions, find the margin of error, E given the following: a. n=18, x = 78.3, s = 2.5, 95% confidence b. n=28, x=90.8, s = 2.8, 99% confidence Solve the following problems. 3. A random sample of 12 students in a certain dormitory has an average weekly expense of Php400 for snad with a standard deviation of Php12.50. Construct a 90% confidence interval for the amount spent on snack assuming the expenses are normally distributed. 4. A quality controller wants to estimate the proportion of high-quality goods out of a batch of products with a 90% confidence level and a margin of error of 5%. How many products must he test? 5. Given a sample size n = 12, sample mean of 120 ml and sample standard deviation of 6. The parent population is normally distributed. Find the error E and the interval estimate of the population mean μ.​