Q1. A small town has a population of 20,000 people. Among these 1,000 regularly visit a popular local bar. A sample of 100 people who visit the bar is surveyed for their annual expenditures in the bar. It is found that on average each person who regularly visits the bar spends about $2000 per year in the bar with a standard deviation of $200. Construct a 99 percent confidence interval around the mean annual expenditure in the bar.
Q2. The production manager for the XYZ manufacturing company is concerned that the customer orders are being shipped late. He asked one of his planners to check the timeliness of shipments for 1000 orders. The planner randomly selected 1000 orders and found that 100 orders were shipped late. Construct the 99% confidence interval for the proportion of orders shipped late.
Q3. The weight of a product is measured in pounds. A sample of 49 units is taken from a batch. The sample yielded the following results: = 80 lbs. and s = 10.5 lbs. Calculate a 90 percent confidence interval for the mean.