Can you assist me in putting together a z test using the information below ... or if we use a different example?

Due to increase in product demand, management needs to increase labor production hours by an estimated 270 hours. Any-Business currently has 30 production employees whose hourly wages varies from $7.50 - $8.50 per hour.

One production manager proposed implementing 9 hours of mandatory overtime for each employee, while another proposed adding 9 new hires who work 30 hours weekly.

Company policy requires that an employee be paid time & ½ for every hour worked over 40 hours in a week. Starting pay for a new hire is $7.50 per hour.

Null Hypothesis:

It is cost less to pay current employees (CE) 9 hour of mandatory overtime than to add 9 new hours (NH) to work 30 hours a week at starting pay.

Alternate Hypothesis:

It costs more to pay current employees (CE) 9 hour of mandatory overtime than to add 9 new hours (NH) to work 30 hours a week at starting pay.