#### Transcript of ENTR 3130 Lecture 07B - SPC

**Statistical Process Control**

Brad Anderson

The purpose of an SPC charts is to use statistical methods to monitor whether your process is in control

What does control mean?

Achieving and maintaining quality is a hard and costly process the requires constant vigilance and improvement.

High quality is not something you ever attain; it is something you always strive for.

**Wrap Up**

Let's look at question 2A (page 416

STEP 1 Does this question use continuous or discrete data?

STEP 2 For our sample, do we have an n=1, or n>1

STEP 3 Given that, what type of SPC chart should we make (see Fig 10-15 on page 410)

STEP 4 Find the right equation to use, and find the numbers to put into each variable.

STEP 5 You'll notice we have this variable z. WTF?

STEP 6 Calculate UCL & LCL

STEP 7 Completed question 2B

So, that's a mean chart. What's the difference between a mean and a range chart? Why is it important to do both?

What if I'm lazy and I don't want to calculate the standard deviation of my sample?

I know, standard deviations are a pain to calculate. Don't worry, though.

See question 3A on page 416

Here, we use a new equation that uses average ranges instead of standard deviations

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