Solutions for Chapter 6: Descriptive Statistics

A fractional factorial experiment with k factors tested in a 2 ? p fraction with all factors tested at only two levels (settings) each

In hypothesis testing, a region in the sample space of the test statistic such that if the test statistic falls within it, the null hypothesis cannot be rejected. This terminology is used because rejection of H0 is always a strong conclusion and acceptance of H0 is generally a weak conclusion

A method of variable selection in regression that examines all possible subsets of the candidate regressor variables. Eficient computer algorithms have been developed for implementing all possible regressions

The average number of samples taken in a process monitoring or inspection scheme until the scheme signals that the process is operating at a level different from the level in which it began.

A second-order response surface design in k variables consisting of a two-level factorial, 2k axial runs, and one or more center points. The two-level factorial portion of a CCD can be a fractional factorial design when k is large. The CCD is the most widely used design for itting a second-order model.

The tendency of data to cluster around some value. Central tendency is usually expressed by a measure of location such as the mean, median, or mode.

The variance of the conditional probability distribution of a random variable.

A tabular arrangement expressing the assignment of members of a data set according to two or more categories or classiication criteria

Another name for factors that are arranged in a factorial experiment.

A control chart in which the point plotted at time t is the sum of the measured deviations from target for all statistics up to time t

Used in statistical quality control, a defect is a particular type of nonconformance to speciications or requirements. Sometimes defects are classiied into types, such as appearance defects and functional defects.

The number of independent comparisons that can be made among the elements of a sample. The term is analogous to the number of degrees of freedom for an object in a dynamic system, which is the number of independent coordinates required to determine the motion of the object.

A management philosophy promoted by W. Edwards Deming that emphasizes the importance of change and quality

The response variable in regression or a designed experiment.

The error sum of squares divided by its number of degrees of freedom.

The numerical value of a point estimator.

A series of tests in which changes are made to the system under study

The distribution of the random variable deined as the ratio of two independent chi-square random variables, each divided by its number of degrees of freedom.

A random variable that generalizes an Erlang random variable to noninteger values of the parameter r

A function that is used to determine properties of the probability distribution of a random variable. See Moment-generating function