Using Graphs

We can tell a great deal about a process by looking at:

• any patterns in the plotted data
• the relationship between the plotted data and the Control Limits

For example, we can ask:

• Is the process producing any steel beams which are too long or short?
• Is it producing lots of beams longer or shorter than 105cm (i.e. the customer's desired length)?
• Is each beam coming off the press a little longer (or shorter) than the one before?