In order to officailly bid on a contract, a contractor wants to be 95% confident that his error is less than two hours in estimating the average time it takes to install tile flooring. previous contracts indicate that the standard deviation is 4.5 hours. how large a sample must be selected?

When eating out, record the total cost of your meal (before tip) and the tip that you left. determine the percent of the cost of the meal that you left as a tip.

1. during first 10 seconds 2. between 10 seconds and 35 seconds 3. during 35 seconds to 40 seconds

Do some research and find a city that has experienced population growth. determine its population on january 1st of a certain year. write an exponential function to represent the city’s population, y, based on the number of years that pass, x after a period of exponential growth. describe the variables and numbers that you used in your equation.