Question

You have joined a major cell phone manufacturer. The weight of a cellphone is very important. A light or heavy phone may indicate a future problem. Much of the weight is in the battery.

You have gathered the weight of eight phones and want to place in a control chart. The chart should cover the center point and the spread of the weights.

1. What chart would you use – attribute or variable?

The following points have been gathered.   Place these into your software and answer the following questions.

Cell Phone Weights

1	2	3	4	5	6	7	8
0.37	0.369	0.366	0.368	0.368	0.37	0.371	0.367
0.369	0.369	0.369	0.369	0.371	0.368	0.372	0.371
0.37	0.367	0.366	0.37	0.37	0.371	0.368	0.37
0.368	0.37	0.37	0.37	0.369	0.373	0.37	0.371

Using Microsoft Excel:

2. What are the number of samples?   

3. What is the sample size?

4. What is the grand average?

5. What is the average range?

6. What is the UCLxbar?

7.  What is the xbar for the third sample?

8.  Does the process seem to be in control?

For above, you have gained some information about the upper and lower specification limits. The upper specification is 0.374 and the lower is 0.364.

Based on these values using Excel:

9. What is the Cp?

10. What is the Cpu?

11. What is the Cpl?

12. What is the Cpk?

Answer 1