Edison is a graduate student living in San Diego who works as a caddy to supplement their normal income. At an hourly wage rate of $15, they are willing to caddy 3 hours per week. Upping the wage to $30 per hour, they are willing to caddy 8 hours per week. Using the midpoint method, the elasticity of Edison's labor supply between the wages of $15 and $30 per hour is approximately , which means that Edison's supply of labor over this wage range is