Exam 15: Statistical Quality Control

In order for a process to be capable,it must have a capability ratio of at least 1.00.

Given the following process control data for a quality attribute (three samples of size 400 each): If the process proportion of defectives is unknown,what are the upper and lower control limits for an alpha risk of .10? .05? .01?

A Quality Analyst wants to construct a sample mean chart for controlling a packaging process.He knows from past experience that whenever this process is under control,package weight is normally distributed with a mean of twenty ounces and a standard deviation of two ounces.Each day last week,he randomly selected four packages and weighed each with the following results: What is the standard deviation of the sampling distribution of sample means?

Six sigma quality refers to achieving process variation so small that the half-width of the design specification equals six times the standard deviation of the process.

The part of statistical quality control that occurs during the production process is known as acceptance sampling.

Which of the following is not needed to calculate sample mean control charts?

"Process capability" compares "process variability" to the "design specifications".

A sample statistic that falls inside the control limits suggests there is assignable variation in the process.

The charted values on a run chart are too spread out.This is an indication of what?

A town's department of public works is concerned about adverse public reaction to a sewer project that is currently in progress.Because of this,the Commissioner of Public Works has authorized a weekly survey to be conducted of town residents.Each week,a sample of 100 residents is questioned on their feelings towards the project.The results to date are shown below.Analyze this data using an appropriate control chart with a 5% risk of Type I error.Is the community sentiment stable? 11eab92b_c48d_537a_99e6_d5f960692523

The main task in process control is to distinguish assignable from random variation.

A Quality Analyst wants to construct a sample mean chart for controlling a packaging process.He knows from past experience that whenever this process is under control,package weight is normally distributed with a mean of twenty ounces and a standard deviation of two ounces.Each day last week,he randomly selected four packages and weighed each with the following results: What value should be used as the mean of the sampling distribution of sample means?