In statistical quality control, the \bar x and R chart is a type of control chart used to monitor variables data when samples are collected at regular intervals from a business or industrial process <br /> <br />The chart is advantageous in the following situations <br /> <br />The sample size is relatively small (say, n ≤ 10—\bar x and s charts are typically used for larger sample sizes) <br />The sample size is constant <br />Humans must perform the calculations for the chart
