540201 Statistics for Engineer. Statistics Deals with Collection Presentation Analysis and use...
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Transcript of 540201 Statistics for Engineer. Statistics Deals with Collection Presentation Analysis and use...
540201Statistics for Engineer
Statistics Deals with
Collection Presentation Analysis and use of data to make decision Solve problems and design products and
processes Can be powerful tool for
Designing new products and systems Improving existing design Designing, developing and improving
production processes
Variability
Collecting Engineering Data Retrospective Study
Would be either all or a sample of the historical process data.
Observational Study Would be either observations of process or
population. Are usually conducted for short time
period. Designed Experiments
Collect the observations of the resulting system output data.
Random Samples Statistical methods work correctly and
produce valid results. Random samples must be used.
Each possible sample of size n has an equally likely chance of being selected.
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Population and Sample Population
◦ An entire group of objects that have been made or will be made, described by a characteristic of interest
◦ Population parameters are unknown and usually unknowable Sample
◦ The group of objects actually measured in a statistical study◦ A sample is usually a subset of the population of interest◦ Sample statistics estimate population parameters
“Population Parameters” “Sample Statistics”m = Population mean
s = Sample standard deviation
Sample
Population
s = Population standard deviation
X = Sample mean
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Population and Sample
Probability(sampling)
Inference(predict)
Population
Parameters:, , r, etc.
Sample
Statistics:x, s, p, r, etc.
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Data type Attribute data
–Discrete, proportion and count of defects are the most common
–We can count Variable data
–Continuous data–We can measure variablesVariable data ให้�ข้�อมู�ลที่�
ดีกว่�า และต้�องการจำ�านว่นข้�อมู�ลน�อยกว่�า
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ParametersPopulation Sample
Mean µ
Variance S2 or SD2
Standard Deviation S or SD
Standard score Z