Statistics and Probability

You measure 31 textbooks' weights, and find they have a mean weight of 37 ounces. Assume the population standard deviation is 13.3 ounces. Based on this, construct a 95% confidence interval for the true population mean textbook weight. Give your answers as decimals, to two places 2 In a survey, 24 people were asked how much they spent on their child's last birthday gift. The results were roughly bell-shaped with a mean of $46 and standard deviation of $19. Construct a confidence interval at a 98% confidence level. Give your answers to one decimal place. Out of 300 people sampled, 63 had kids. Based on this, construct a 95% confidence interval for the W true population proportion of people with kids. Give your answers as decimals, to three places