You want to obtain a sample to estimate a population mean. Based on previous evidence, you believe the population standard deviation is approximately 0' = 22-3. You would like to be 9096 confident that your esimate is within 2.5 of the true population mean. Hov.r large of a sample size is required? Do not round mid-calculation. However, use a critical value accurate to three decimal places this is important for the system to be able to give hints for incorrect answers. 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 $31 and standard deviation of $10. Find the margin of error at a 99% confidence level. Give your answer to two decimal places.You want to obtain a sample to estimate a population proportion. At this point in time, you have no reasonable estimate for the population proportion. You would like to be 98% confident that you esimate is within 0.2% of the true population proportion. How large of a sample size is required? n = Do not round mid-calculation. However, use a critical value accurate to three decimal places.Assume that a sample is used to estimate a population mean ILL. Find the 90% confidence interval for a sample of size ll} with a mean of 45.9 and a standard deviation of 19.3. Enter your answer as an open- interval [11 9., parentheses] accurate to one decimal place {because the sample statistics are reported accurate to one decimal place]. Answer should be obtained without any preliminary rounding. However, the critical value mayr be rounded to 3 decimal places. You measure 39 textbooks' weights, and find theyr have a mean weight of 44 ounces. Assume the population standard deviation is 8.4 ounces. Based on this, construct a 90% confidence interval for the true population mean textbook weight. Give your answers as decimals, to two places _