1. Parts manufactured by an injection molding process are
EMIS 5364/STAT Homework 12
Injection Molding
Parts manufactured by an injection molding process are
subjected to a compressive strength test. Twenty samples
of five parts are collected, and the compressive strengths
(in psi) are shown in the following table.

2. Injection Molding Sample # x1 x2 x3 x4 x5
EMIS 5364/STAT Homework 12
Injection Molding
Sample # x1 x2 x3 x4 x5

3. (b) After establishing the control charts in part a, 15 new
EMIS 5364/STAT Homework 12
Injection Molding
(a) Establish x and R control charts for compressive strength using these data. Is the process in statistical control?
(b) After establishing the control charts in part a, 15 new
subgroups were collected (Production Data) and the compressive strengths are shown next. Plot the x and R values against the control limits from part a and draw conclusions.

4. Injection Molding Production Data EMIS 5364/STAT 5344 Homework 12
Sample # x1 x2 x3 x4 x5