SPC for Excel contains three major methods of determining if there are significant differences in the treatment (process) means. These include Fisher's LSD method, Tukey's method, and Bonferroni's method. Equality of variances is tested using Bartlett's method or Levene's method. In each method, the software clearly tells you if significant differences are found and which treatment means or variances are different. The software also contains the Analysis of Means method to determine if there are significant differences in treatment means. Box and Whisker plots give a visual picture of the median locations and the spread in the data.

Multiple Process Comparison Features

• Fisher LSD, Bonferroni and Tukey's Method
  • Stacked or unstacked data entry
  • ANOVA table
  • Count, mean, standard deviation, variance by treatment
  • Family confidence interval
  • Individual confidence interval
  • Confidence interval for each pair of treatments
  • Yes/No decision if pairs are different or the same
  • Yes in red if significant difference
  • Plot of confidence intervals
• Bartlett's and Levene's Method
  • Stacked or unstacked data entry
  • Count, mean standard deviation, variance by treatment
  • Test statistics
  • Chi square critical value
  • p value
  • Decision if the variances are the same
• Analysis of Means
  • Table of results including average, maximum, minimum, range, treatment variance, treatment degrees of freedom, overall average, average range, H, and lower/upper decision limits
  • Control charts with different treatment means plotted in red
• Box and Whisker Plots
  • Median
  • 25% and 75% quartiles
  • Minimum
  • Maximum

Examples of Output

Confidence Interval Plot

Bartlett's Test for Equality

Analysis of Means

Box and Whisker Plots