Learn the usefulness of confidence intervals in your Six Sigma project during this video.
- Let's say you're interested in determining the mean height…of the employees in your company,…but there are 500 employees.…It's not practical to measure every one of them.…So, you take a sample of 20 employees…and find that the sample mean is 69.87 inches.…How confident are you in saying that the population mean…is exactly 69.87 inches?…You probably have a zero percent confidence level.…Now, how confident will you be in saying…that an interval of zero to 100 inches…includes the population mean?…Now you're probably 100% confident.…
But having a 100% confidence level…with such a wide interval is not useful.…That interval is called the confidence interval,…which is a statistically calculated range of values…that contains a population parameter, such as the mean,…with a certain level of confidence.…It's most commonly set at 95%.…Here is a graphical summary of the sample data…for mean height using Minitab.…You can see the sample size is 20…along with all the summary statistics.…
The sample mean is 69.871.…The 95% confidence interval for the mean is 69.036…
Author
Richard Chua
Released
5/25/2017Dr. Richard Chua builds upon his Six Sigma: Green Belt, Six Sigma Foundations, and Learning Minitab courses—which are prerequisites to this course—and covers an array of topics, including measurement system analysis, hypothesis testing, response surface methods, displaying improved process capabilities, and more.
- Process flow metrics
- Measurement system analysis
- Calculating process capability
- Hypothesis testing
- Confidence intervals
- Testing for normality
- Designing, conducting, and analyzing full-factorial experiments
- Using fractional factorial experiments for screening
- Displaying improved process capability
Skill Level Intermediate
Duration
Views
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Introduction
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Welcome1m 38s
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Certification information1m 31s
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Exercise files34s
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1. Define Phase
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Overview of the Define phase3m 51s
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2. Measure Phase
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Process flow metrics3m 34s
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Sample sizes3m 7s
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3. Analyze Phase
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Hypothesis testing road map3m 33s
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Confidence intervals3m 14s
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Test for normality2m 49s
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Compare variances5m 16s
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T-tests6m 4s
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ANOVA3m 55s
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Contingency tables6m 49s
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Nonparametric tests6m 49s
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Correlation3m 45s
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Linear regression4m 38s
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Multiple regression5m 5s
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4. Improve Phase
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Full-factorial experiments9m 19s
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DOE with curvature6m 27s
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Response surface methods8m 37s
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5. Control Phase
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SPC chart selection4m 46s
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SPC chart analysis5m 1s
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Conclusion
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Next steps56s
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Video: Confidence intervals