Question

The following are quality control data for a manufacturing process at Kensprt Chemical Company. The data show the temperature in degrees centigrade at five points in time during the manufacturing cycle. The company is interested in using quality control charts in monitoring the temperature of its manufacturing cycle. Construct an X bar and R chart and indicate what its tells you about the process.

Sample      X bar      R

     1            95.72    1.0

     2            95.24      .9

     3            95.38      .8

     4            95.44      .4

     5            95.46      .5

     6            95.38    1.1

     7            95.40      .9

     8            95.44      .3

     9            95.08      .2

    10           95.50      .6

    11           95.80      .6

    12          95.22      .2

    13           95.56    1.3

    14           95.22      .5

    15           95.74      .8

    16          95.72     1.1

    17          94.82       .6

    18          95.46       .5

    19          95.60       .4

    20          95.64       .6

Answer 1

Solution: Here concept of x bar and R chart is used.

From the X bar chart, clearly the process is out of control because one point lies outside of the control limit.

In R chart, since all the points lie within the control limits, so this chart shows that process variability is in control.