The National Bank, like most other large banks, found that using automatic teller machines (ATMs) reduces the cost of routine bank transactions. National installed an ATM in the corporate offices of the Fun Toy Company. The ATM is for the exclusive use of Fun's 581 employees. After severa employees in a month: \begin{tabular}{cc} Number of Times & W ATM Used & Frequency $\theta$ & 15 W 1 & 20 2 & 10 3 & 15 4 & 15 5 & 25 W \hline \end{tabular} a. What is the estimate of the proportion of employees who do not use the ATM in a month? Proportion b-1. For estimate of the proportion of employees who do not use the ATM in a month, develop a $80 %$ confidence interval. (Round the final answers to 3 decimal places.) SP.VS.871