1. CHAPTER 5 Fundamentals of Statistics
Quality Control
Source: Besterfield, Dale H., Quality Control.

2. Introduction Definition of Statistics
quantitative data
football statistics
employment statistics
science that deals with data
collection
tabulation
analysis
presentation
decisions concerning quality

3. Introduction Definition of Statistics
descriptive or deductive statistics
describe and analyze
deals with subject or group
inductive statistics
uses limited amount of data (sample)
important conclusion about a population
conclusions or inferences
cannot be stated with absolute certainty
language of probability

4. Introduction Collection of Data
data collected for quality purposes
quality characteristics
variables
numerical value
measurable
weight measured in grams
attributes
no numerical value
conforming or not conforming
“go/no go gage”

5. Introduction Collection of Data
continuous variables
weight of a gray iron casting
11 kg, kg or kg
accuracy of the measuring instrument
discrete variables
number of nonconforming rivets in a trailer
0, 3, 5, 10 or 96
continuous variables are measurable
discrete data are countable

6. Introduction Collection of Data
Significant figures
digits exclusive of any leading zeros
3.69 has three significant figures
has five significant figures
2700 has four significant figures
has six significant figures
has three significant figures
trailing zeros are counted as being significant
leading zeros are not significant

7. Introduction Collection of Data
Significant figures
multiplication, division, and exponentiation
answer has the same number of significant figures as the number with the fewest significant figures

8. Introduction Significant figures
addition and subtraction
with decimal points - final answer can have no more significant figures after the decimal point than the number with the fewest significant figures after the decimal point
without decimal points - final answer has no more significant figures than the number with the fewest significant figures

9. Frequency Distribution Ungrouped Data
comprise a listing of the observed values
grouped data
lumping together of the observed values

10. Frequency Distribution Ungrouped Data - Histograms

11. Frequency Distribution Ungrouped Data - Histograms

12. Frequency Distribution Ungrouped Data
in-class example
create a relative cumulative frequency histogram
given the following frequency distribution

13. Frequency Distribution Ungrouped Data
In class example: next step involves creating a relative cumulative frequency histogram from the following:

14. Frequency Distribution Grouped Data
Determining cell intervals for “grouped data”
Collect data and construct a tally sheet
Determine the range
Determine the cell interval which is the distance between adjacent cell midpoints
In general, the number of cells should be between 5 and 20
round down to the nearest odd number
n = sample size

15. Frequency Distribution Grouped Data

16. Frequency Distribution Grouped Data

17. SME
Computer Aided Design 20 min