A study was conducted to analyze the amount of time spent sitting at a desk for employees over a work day.The time spent sitting was recorded for a large sample of employees and found to follow a bell-shaped distribution with a mean of about 280 minutes.The smallest amount of time was 100 minutes and the greatest amount of time was 460 minutes. Unfortunately, the standard deviation was not reported in the summary. Which of the following represent the most appropriate value for that standard deviation?

• 60 minutes
• 90 minutes
• 180 minutes
• 360 minutes