A group of 50,000 tax forms has an average gross income of $37,000, with an SD of $20,000. Furthermore, 20% of the forms has a gross income over $50,000. A group of 900 forms is chosen at random for an audit. To estimate the chance that between 19% and 21% of the forms chosen for an audit have gross incomes over $50,000, a box model is needed.

The number of tickets in the box will be [a]. 

Each ticket in the box shows [b]. 

The SD of the box is $20,000. This statement is [c]. 

The number of draws is 900. This statement is [d]. 

The chance (approximately) that between 19% and 21% of the forms chosen for audit have gross incomes over $50,000 is [e]%. (if the chance cannot be found type 'NA')

The chance (approximately) that between 9% and 11% of the forms chosen for audit have a gross income over $75,000 is [f]%. (if the chance cannot be found type 'NA')