Why do data analysis? Brilliantly put in the movie Moneyball, and applicable to Six Sigma, it’s so we can get past biases and to to truth. We must be careful. The goal isn’t to eliminate judgement. We want to use data to make better decisions.

## Using Data to Make Better Decisions

Great TED presentation on using data to make better decisions.

## Outline for Performing Data Analysis

• Discrete Data Tools & Examples
• Discrete / Attribute / Categorical
• Yes / no. Pass / fail. IGO / NIGO.
• Is counted
• Percentages & Ratios
• Categories
• Good for failure analysis / making decisions (good vs bad; correct vs incorrect; accepted vs rejected)
• Tools
•  Defects / Defectives vs Fixed / Varying

## Continuous Data Tools & Examples

• Continuous / Variable
• Can be subdivided / exists on a continuum.
• Ex. Weight, speed, temp, time, cost
• More options to answer a question because the scale can be repeatedly broken down.
• Ex 5k times
• Tools
• Vs nothing / itself (frequency)
• Types +use when
• All: show relative frequency
• Dot plots
• Fine distinctions needed
• Small size
• Box plots
• Focus on the size of the percentiles
• Large / broad distributions of data
• Histograms
• Provides a clear shape
• Use when the overall shape is more important than the individual values
• Used with larger data sets
• Example
• Possible outcomes to watch for
• All
• Shows time-related patterns (trends, shifts, etc)
• Run Charts
• Control Charts
• Continuous Driver
• Scatter plots
• Don’t usually get a straight line, but if you do there is likely meaning.

## Doing statistical data analysis usually involves the following:

1. Measuring of the central tendency.
2. Measure of the variation.
3. Evaluation of the shape of the data.
1. A histogram is useful in evaluating the shape of the data.
4. 4 Questions of Data Analysis (nice flow chart): http://www.spcpress.com/pdf/DJW204.pdf

## Contributors

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