A city plans to pay for a new public parking garage through parking fees. They need an accurate estimate of the mean daily income from parking fees. For a short period of time, daily fees collected varied with a standard deviation about $14. How many days' worth of data must they collect to have 95% confidence of estimating the true mean to within $3? (Round up to the nearest whole number as needed.) Using a sample mean and known population standard deviation, , the following 95% confidence interval was constructed: 2912 <