Text this: Economic design of exponential chart for monitoring time-between-event data under random process shift

  _____      ___     _    _     _____    _    _   
 / ____||   / _ \\  | |  | ||  |  ___|| | || | || 
/ //---`'  | / \ || | |/\| ||  | ||__   | || | || 
\ \\___    | \_/ || |  /\  ||  | ||__   | \\_/ || 
 \_____||   \___//  |_// \_||  |_____||  \____//  
  `----`    `---`   `-`   `-`  `-----`    `---`