Final answer:
Option 1: The x-bar control chart is used to monitor variations in a process by tracking the average value of the process over time.
Step-by-step explanation:
The type of control chart used to monitor variations in a process is the x-bar chart. This chart tracks the average value of a process over time. It is commonly used to monitor variations in a manufacturing or production process.
In an x-bar chart, you calculate the average of a sample of measurements taken from the process and plot them on the chart. The center line on the chart represents the overall average of the process, while the upper and lower control limits represent acceptable variations. Any data points outside of the control limits indicate an out-of-control process.
For example, let's say you are monitoring the weight of packed cereal boxes on a production line. You collect samples of 10 boxes every hour and calculate the average weight. By plotting these averages on an x-bar chart, you can easily monitor if the process is within the acceptable weight range or if there are any variations.