RESEARCH ASSISTANTS

MAHDI SHAVARANI &

FARAMARZ KHOSRAVI

Weight

Percentage

of Cotton

x 7 7 15 11 9

y 12 17 12 18 18

z 14 18 18 19 19

w 19 25 22 19 23

q 7 10 11 15 11

Observed Tensile Stregth

Please enter the data shown below in to the SPSS:

Example: The city manager is concerned with water

usage particularly in single family homes. She would like to develop a plan to reduce the water usage in the city. To investigate she selects a sample of 100 homes and determines the typical daily water usage for various purposes.

import data from Excel file(Pareto sheet) to SPSS

If she want to improve quality of water usage, which reason is the main problem?

We may plot the run chart to see the trends.

The table shows the pH values of Dye compound

Is there any trend in our data?

Usage: to check the relation between variables.

Example;

Check the relationship between the gender and the

job classification

ID Name Gender Height Weight Job Classification

1 A M 165 60 Job Type 1

2 B F 155 50 Job Type 2

3 C F 157 62 Job Type 1

4 D M 175 68 Job Type 2

5 E F 178 70 Job Type 3

6 F M 163 65 Job Type 2

7 G M 158 55 Job Type 1

8 H F 162 68 Job Type 3

9 J M 164 65 Job Type 2

Please open the excel file that you download from the course web page. And copy and paste the data to the Spss program.

The use of statistical methods and techniques to evaluate the quality of products and processes in order to monitor (usually using control charts) and where necessary improve their quality (by doing corrective actions). These methods use statistical sampling of products which are checked for defectives to determine whether or not the process is in control.

A control chart graphically represents statistics of repeated samples of a production process in time. If fact, a control chart is a time series plot of a statistic. It consists of points representing a statistic, a center line, and upper and lower control limits. It may consists of the mean of this statistic, the standard error of the statistic, upper and lower warning limits, and so on.

Variation in production is a key aspect of quality control. It is assumed to arise from two different main sources:

- Common causes (un-controllable factors)

- Assignable causes (operator fatigue, tools wearing out, incorrect machine settings)

A process is considered in control, when there are no assignable causes. If the outcome of a statistic is outside the control limits, then the process is considered out of control.

Consider a process by which coils are manufactured. Samples size 5 are randomly selected from the process and the resistance values of the coils are measured.

Please open the excel file that you download from the course web page. And copy and paste the data to the Spss program.

Delete samples 22, 23 and revised the control limits.

Notice that sample 15 falls silightly above the upper control limits so delete sample 15 and revised the control limits.

THANKS FOR YOUR

ATTENTION For further information :

Faramarz.khosravi@cc.emu.edu.tr

Mahdi.shavarani@cc.emu.edu.tr