Chapter 3

Statistical Models or Quality Control Improvement

•Easy to find percentiles of the data; see page 43

Stem-and-Leaf Display

•Also called a run chart

Marginal plot produced by MINITAB

Plot of Data in Time Order

•Group values of the variable into bins, then count the number of observations that fall into each bin

•Plot frequency (or relative frequency) versus the values of the variable

Histograms – Useful for large data sets

Histogram for discrete

data

Numerical Summary of Data

The Box Plot(or Box-and-Whisker Plot)

Comparative Box Plots

The Hypergeometric Distribution

Basis is in Bernoulli trials

The random variable x is the number of successes out of n Bernoulli trials with constant probability of success p on each trial

The Binomial Distribution

Frequently used as a model for count data

The Poisson Distribution

The Normal Distribution

Original normal distribution

Standard normal distribution