# Nice Topics: Standard deviation, Statistics, Arithmetic mean, Normal distribution / Pages: 4 (844 words) / Published: Jan 24th, 2013

Group 6
Quality Associates Inc.
Statistics pg 396:

Stalita Rembert
Jennifer Orso
Jeffery Payne
Janice Seawright

Case Overview:

Quality Associates, Inc., a consulting firm, advises its clients about sampling and statistical procedures that can be used to control their manufacturing processes. IN one particular application, a client game quality associates a sample of 800 observations taken during a time in which that client's process was operating satisfactorily. The sample standard deviation for there data was .21 ; hence, with so much data, the population standard deviation was assumed to be .21. Quality associates then suggested that random samples of size 30 be taken periodically to monitor the process on an ongoing basis. BY analyzing the new samples, the client could quickly learn whether the process was operating satisfactorily. When the process was not operating satisfactorily, corrective action could be take to eliminate the problem. the design specification indicated the mean for the process should be 12. The hypothesis test suggested Quality Associates follows.  : μ=12 : μ12
Corrective action will be take any time H0 is rejected.
The following samples were collected at hourly intervals during the first day of operation of the new statistical process control procedure. These data are available in the data set Quality . Sample 1 | Sample 2 | Sample 3 | Sample 4 | 11.55 | 11.62 | 11.91 | 12.02 | 11.62 | 11.69 | 11.36 | 12.02 | 11.52 | 11.59 | 11.75 | 12.05 | 11.75 | 11.82 | 11.95 | 12.18 | 11.90 | 11.97 | 12.14 | 12.11 | 11.64 | 11.71 | 11.72 | 12.07 | 11.80 | 11.87 | 11.61 | 12.05 | 12.03 | 12.10 | 11.85 | 11.64 | 11.94 | 12.01 | 12.16 | 12.39 | 11.92 | 11.99 | 11.91 | 11.65 | 12.13 | 12.20 | 12.12 | 12.11 | 12.09 | 12.16 | 11.61 | 11.90 | 11.93 | 12.00 | 12.21 | 12.22 | 12.21 | 12.28 | 11.56 | 11.88 | 12.32 | 12.39 | 11.95 | 12.03 | 11.93 | 12.00 | 12.01 | 12.35 | 11.85 | 11.92 | 12.06 | 12.09 | 11.76