11. Calculating the price elasticity of supply Amy is a volunteer fire fighter living in Detroit who works as a caddy to supplement their normal income. At an hourly wage rate of $40, they are willing to caddy 9 hours per week. Upping the wage to $55 per hour, they are willing to caddy 17 hours per week. Using the midpoint method, the elasticity of Amy's labor supply between the wages of $40 and $55 per hour is approximately , which means that Amy's supply of labor over this wage range is