CALCULATORS

Pragmatic Improvement trains clients on MINITAB Statistical Software ® - a widely accepted statistical tool for which licences are easily obtainable through Pragmatic Improvement. Using specifically designed software will reduce the amount of manual calculations, which would otherwise be the case if using accounting spreadsheet software. Pragmatic Improvement can use either software with your company.

Sample Size Calculations

It is not always feasible to measure the total volume or population, so sample size calculators make the task quick and easy. Firstly, consider the size of your sample to obtain an acceptable margin of accuracy.

Example
Consider a common form of sampling; tasting soup from a pot. If the soup is well stirred, a spoonful will tell us how the entire pot tastes. Now consider tasting the soup by dipping only a toothpick into it. This may be too small a sample to provide an accurate impression of how the soup tastes; we need at least a spoonful. In the same way, the size of the sample is what determines how precisely statistics from that sample describe the population. But the sample size has the same effect regardless of the population size.

• Sample Size For Continuous Data
  Measurement of a continuous incremental scale. i.e.
  • Time
  • Distance
  • Weight
• Sample Size For Discrete Data
  Counts within categories, proportions. i.e.
  • Defect/Non-defect
  • Male/Female
  • Liberal/Conservative

Process Sigma

Defects Per Million Opportunities (DPMO) is the average number of defects per unit observed during an average production run divided by the number of opportunities to make a defect on the product under study during that run normalised to one million.

• Use our online Process Sigma calculator