When the manufacturing process for AA batteries is in control, the average battery life is 7.5 hours, or 450 minutes. For 10 sequential samples of nine batteries each that were placed in a rack that...

When the manufacturing process for AA batteries is in control, the average battery life is 7.5 hours, or 450 minutes. For 10 sequential samples of nine batteries each that were placed in a rack that systematically drains the batteries to simulate everyday battery usage, the sample battery life averages are found to be: 460, 450, 440, 470, 460, 450, 420, 430, 440, and 430 minutes. Prepare a run chart for these sample results.