A machine tool vender wants to sell an injection molding machine. The current machine produces 3.2% defectives. A sample of 1100 from the vender’s machine has 2.9% defective. Do these numbers indicate that the proposed machine has a lower rate of defectives?

Deming called the technique of studying a sample to gain understanding of the distribution of a population an “enumerative study.” His main objection to these studies was:

The word “champion” in the context of Six Sigma projects refers to:

What percent of population falls below the lower specification limits?

A population of size 1,000,000 has mean 42 and standard deviation 6. Sixty random samples, each of size 15 are selected. According to the Central Limit Theorem the distribution of the sixty sample means has a mean of approximately:

The operators of a manufacturing cell work out a more orderly arrangement for tool storage and establish a schedule to maintain cleanliness on a daily basis. These improvements are best described by which approach to problem solving?

(Refer to the previous problem) The variance of the five replications for each run is calculated. Most of these variances are approximately equal but two are significantly lower than the others. The experimenters would be especially interested in those two runs if they want to optimize:

When σ = 10, what sample size is needed to specify a 95% confidence interval of ±3 units from the mean?

Find Cp and Cpk.

The time for a fail-safe device to trip is thought to be a discrete uniform distribution from 1 to 5 seconds. To test this hypothesis, 100 tests are conducted with results as shown below.

On the basis of these data, what are the chi square (χ2) value and the number of degrees of freedom (df)?

x2 df