Central tendency is the idea that when using normal data, all three of the main measures (mean, mode, median) tend to be roughly the same.
Standard deviation is the measure of variation in a process. Describing variation by standard deviations lets us easily compare processes.
Dispersion is the degree of variation in the data. In other words, the extent of the spread of values from the mean.
A data collection form is a best practice of data collection. It’s a way of recording your approach to obtaining the data you need to perform your analysis.
A response plan sets out what to do if a process doesn’t meet one of the quality assurance requirements in the control plan.